ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (73)
  • Data
  • 42.60  (39)
  • 72.40  (34)
  • Springer  (73)
  • Blackwell Publishing Ltd
  • ELSEVIER
  • Elsevier
  • Macmillian Magazines Ltd.
  • Molecular Diversity Preservation International
  • 2020-2022
  • 1990-1994  (29)
  • 1985-1989  (44)
  • 1945-1949
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (73)
  • Natural Sciences in General
Collection
  • Articles  (73)
  • Data
Keywords
Publisher
  • Springer  (73)
  • Blackwell Publishing Ltd
  • ELSEVIER
  • Elsevier
  • Macmillian Magazines Ltd.
  • +
Years
Year
Topic
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (73)
  • Natural Sciences in General
  • Physics  (221)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 59 (1994), S. 579-582 
    ISSN: 1432-0630
    Keywords: 42.65 ; 42.70 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Two-beam coupling gain and speed of a Cr-doped strontium-barium niobate single crystal at 514.5 nm and 632.8 nm are measured to compare photorefractive origins and responses. The same single deep center and single carriers are found to be responsible for the observed photorefractivities at both wavelengths. Self-pumped phase-conjugate reflectivities are also measured at both wavelengths.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 58 (1994), S. 87-90 
    ISSN: 1432-0630
    Keywords: 72.40 ; 73.60 ; 81.15
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Recombination and transport parameters were determined in Schottky diodes made of thin TiO2 solgel films with particle size around 50 nm. Effective recombination times are typically in the range, 10 μs〈τ〈1 ms, depending on injection level. The lifetimes are found to decrease at higher current levels, indicating bimolecular recombination kinetics due to a progressive increase in trap occupation. The mobility-lifetime product is estimated to be ≈5×10−11 cm2/V and is independent of current level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 59 (1994), S. 563-567 
    ISSN: 1432-0630
    Keywords: 61.70 ; 72.40 ; 78.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Photoconductivities and photovoltaic currents of ruthenium-doped KNbO3 are orders of magnitude larger than that of undoped and ion-doped crystals. KNbO3:Ru is very sensitive for holographic recording with red light and the photovoltaic current increases sublinearly with light intensity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0630
    Keywords: 52.25 ; 42.60 ; 35.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This work deals with the study of a plasma produced by intense XeCl-excimer-laser irradiation of a titanium surface in nitrogen-containing atmospheres. We observed that the optical emission spectra resulting from irradiation of Ti targets in various ambient atmospheres (N2, NH3, N2+H2 mixtures) contain lines of atomic and ionized species of the irradiated target material only. The spectra are almost independent of the ambient atmosphere. The expansion velocities of atomic and ionic species in the plasma plume were obtained by time-of-flight measurements at different distances from the target. Mass spectrometry measurements are also performed at low background pressure to identify non-emitting species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 58 (1994), S. 423-429 
    ISSN: 1432-0630
    Keywords: 02.00 ; 42.60 ; 81.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A model was developed to investigate the effect of polarization on laser-induced surface-temperature rise in absorbing materials. GaAs is taken as a substrate material in this study. The polarization was found to significantly affect the laser-induced temperature rise on the substrate surface. This is due to the different surface absorption for the beams with different polarization directions. The laser beam with p polarization can induce higher temperature rise than that with s polarization. If the substrate has a high imaginary value in the complex refractive index, the peak laser-induced surface temperature falls concurrently. A similar effect of polarization to the laser-induced surface temperature rise can be expected to all other absorbing materials.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 58 (1994), S. 471-474 
    ISSN: 1432-0630
    Keywords: 42.60 ; 74.70 ; 73.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Thin films of YBa2Cu3O7 coated with a photoresist have been patterned by means of XeCl- and KrF-excimer-laser light projection. Lines with widths down to 3.5 μm have been fabricated without degradation in T c and j c. The technique is compared with wet-chemical etching and with ns and fs excimer-laser patterning of films without a protective layer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 59 (1994), S. 209-213 
    ISSN: 1432-0630
    Keywords: 42.60 ; 81.15 ; 61.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Irradiation of ceramic alumina (Al2O3) with 248 nm and 308 nm excimer-laser light results in an activation of the surface for subsequent electroless copper deposition. The dependence of this activity on laser parameters, ambient atmosphere during irradiation, and pattern size is described. The results are tentatively explained by changes in the chemical and electrochemical properties of irradiated areas.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 57 (1993), S. 437-440 
    ISSN: 1432-0630
    Keywords: 78.20 ; 61.70 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Holograms recorded under suitable conditions in photorefractive BaTiO3 exhibit an unusual dark build-up. The diffraction efficiency increases by some orders of magnitude after the recording beams are switched off, and then steadily decreases afterwards. An interpretation of this effect in terms of a two-center charge transport model is given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 57 (1993), S. 243-247 
    ISSN: 1432-0630
    Keywords: 42.60 ; 42.80 ; 42.10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract On the basis of the Helmholtz equation the far-field distribution is derived for double heterostructure lasers. The results show that the far-field distribution in the direction normal to the junction plane approaches a Lorentzian function, but parallel to the junction it may be approximated by a Gaussian function. The far-field intensity patterns have “analogous elliptic” form. It is also shown, for the first time, that the separability condition is not strictly valid for the far-field of a laser diode. Only in the vicinity of the optical axis the field can be expressed as a product of two separate functions, each of which depends only on one of the two transverse coordinates parallel and perpendicular to the diode junction.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-0630
    Keywords: 42.80 ; 72.40 ; 68.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Pb1−x−y Sn x Ge y Te:In epitaxial films are examined in a wide temperature interval and at various background fluxes. These films have high sensitivity to infrared radiation in the spectral range λ〈20μm. The lifetime depends exponentially on temperature and varies from several seconds at T=10 K to 10−2 s at T=20 K. The two-electron model of Jahn-Teller centers is proposed to explain the results. Multielement photoresistors based on these films are fabricated and D*=1.7×1013 cm Hz1/2 W−1 at T=25 K is achieved. Noise of the photoresistors is independent of background flux when it varies from 1012 cm−2 s−1 to 1018 cm−2 s−1. As compared with Si:Ga and Ge:Hg photoresistors, the responsitivity is several orders larger at the operating temperature 25–30 K.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 57 (1993), S. 427-430 
    ISSN: 1432-0630
    Keywords: 71.55 ; 72.20.Jv ; 72.40 ; 72.80.Ey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Time-resolved photoconductivity measurements have been used to characterize electron traps in wide-gap n-HgO0.3Cd0.7Te for the first time. The characterization was made possible by combining the time-resolved photoconductive data with the analytical method conventionally used in DLTS spectroscopy. Two electron traps were found in the band gap with 61 meV and 79 meV below the conduction band edge, their concentrations are 1.1×1013 cm−3 and 5.8×1011 cm−3, respectively. Compared with DLTS spectroscopy, this characterization method markedly simplifies sample preparation and experimental procedure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 56 (1993), S. 329-333 
    ISSN: 1432-0630
    Keywords: 42.60 ; 61.80 ; 68.35
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A new kind of surface structure was observed on polyethylene-terephthalate (PET) foils after 248 nm KrF-excimer-laser irradiation in vacuum. The laser fluences employed were around the ablation threshold. The branched fractal structures observed have a lateral dimension in the micrometer range and a heigth of 30 to 60 nm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 56 (1993), S. 335-341 
    ISSN: 1432-0630
    Keywords: 72.40 ; 85.30 ; 85.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The effect of signal-modulated optical radiation on the characteristics of a GaAlAs/GaAs MODFET has been studied analytically. It is found that the offset voltage increases with modulation frequency and the effect of frequency is negligible above 5 MHz. The drain-source current decreases with increase in signal frequency at a constant radiation flux density, doping concentration and drain-source voltage. Studies on sheet concentration and transconductance also show that the signal frequency has a significant effect upto a certain modulation frequency (≲5 MHz) above which the effect of frequency is insignificant.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 56 (1993), S. 417-423 
    ISSN: 1432-0630
    Keywords: 42.60 ; 82.65 ; 73.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Ablation of the surface of a polyimide (Kapton™) film by single pulses of 248 nm or 308 nm radiation (∼20 ns) or 9.17 μm laser radiation (∼170 ns) was studied by photographing the emergence of the blast wave and the plume by a pulse (〈1 ns; 596 nm) of visible laser light. The dynamics of the blast wave was similar in the ultraviolet and in the infrared but the composition of the plume was obviously different. A mass of opaque solid material was ejected for as long as 2.6 μs following the IR pulse in contrast to the minute amount of solids that are seen in the ablation by UV laser pulses of ns duration. UV laser pulses of 50–400 μs duration interact with polyimide surfaces in a manner that is similar to IR laser pulses of ns duration or longer. Chemical analysis of the ablation products that are obtained under various conditions of ablation when compared to the known modes of thermal degradation of polyimide show that the reaction is a thermal process when IR laser pulses or UV laser pulses of long (〉10 μs) duration are employed. Ablation by ns UV laser pulses differs fundamentally in the chemistry of the products from all of the cases mentioned above.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    ISSN: 1432-0630
    Keywords: 42.65 ; 42.70 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We present new results on the growth of semi-insulating vanadium-doped cadmium telluride crystals and their characterization by different optical techniques such as photoinduced current transient spectroscopy, absorption, photoconductivity spectra, and photorefractive wave mixing. Our joint research program aims at developing optimized crystals for efficient optical processing in the near infrared through the photorefractive effect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 54 (1992), S. 363-368 
    ISSN: 1432-0630
    Keywords: 42.60 ; 42.70 ; 81.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Ablation of fused silica using standard excimer lasers (20–30 ns pulse duration at 193, 248, and 308 nm) and a short pulse laser system (500 fs at 248 nm) is reported. Ablation rates range from several hundred nm/pulse (193 nm or fs-laser) up to about 6 μm/pulse (308 nm). The performance of the ablation is found to depend not only on wavelength and pulse duration but also on the existing or laser induced surface quality (e.g., roughness) of the material. Special ablation phenomena are observed. At 193 nm and moderate fluence (3 J/cm2) ablation takes place at the rear side of a plate without affecting the front side, whereas at higher fluence normal ablation at the front side occurs. At 248 nm (standard excimer) the existence of two consecutive ablation phases is observed: smooth ablation at low rate is followed by explosive ablation at high rate. Using fs-pulses smooth shaped holes are formed during the first pulses, whereas high pulse numbers cause the development of a ripple structure in the ablation craters. The results lead to the conclusion that two different ablation mechanisms are involved: the first is based on two photon bulk absorption, the second on controlled surface damage in relation with (partially laser induced) singularity conditions at the surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 55 (1992), S. 61-64 
    ISSN: 1432-0630
    Keywords: 42.65 ; 42.70 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We report on the photorefractive properties of a Cr-doped (K1−x Na x )2A−2 (Sr y Ba1−y )2−A Nb10O30 (x=0.586, y=0.659, A=1.12) single crystal in the near-infrared spectrum. The sample exhibits photorefractivity for wavelengths up to at least 840 nm where the steady-state two-beam coupling gain is found to be larger than 2 cm−1. Photorefractive gain and decay rate are measured as a function of wavelength, grating spacing and intensity. The wavelength dependence of gain fluctuations in two-beam coupling are also measured.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 55 (1992), S. 49-54 
    ISSN: 1432-0630
    Keywords: 42.40 ; 72.40 ; 78.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We report the presence of quasipermanent effects of photochromic and hole-photorefractive nature in Bi12TiO20 (BTO) at low irradiance at 514.5 nm. A new selective two-wave mixing (S2WM) detection technique was used that allows to separately detect phase and amplitude gratings. S2WM is used in this work for operating a self-stabilized recording setup which allows to produce unusually large quasipermanent effects. We also show that stabilized recording is necessary to obtain reliable information from hologram erasure experiments. Results reported in this paper show the complex nature of recording in BTO and the capabilities of stabilized recording and S2WM for fundamental and applied research on photorefractive crystals.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 54 (1992), S. 68-71 
    ISSN: 1432-0630
    Keywords: 7340L ; 72.40 ; 72.20J ; 72.80E
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In the present work the photoconductive response of low resistivity, n-type GaAs epitaxial layers is studied by experimentally monitoring the dependence of the photoconductive gain (PG) optoelectronic parameter upon incident photon flux and temperature. The characterized samples fall into three major categories: ion implanted (II) GaAs epilayers formed within undoped, semi-insulating GaAs substrates; GaAs epitaxial layers grown by liquid phase epitaxy (LPE) on Cr-doped, semi-insulating GaAs substrates; and ungated GaAs MESFETs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 55 (1992), S. 119-120 
    ISSN: 1432-0630
    Keywords: 42.60 ; 61.40 ; 68.35
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The formation of nap-type and wall-type structures on laser-irradiated polyimide (PI) films is reported for the first time. These investigations demonstrate that such structures can develop on non-melting polymer surfaces.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 55 (1992), S. 269-273 
    ISSN: 1432-0630
    Keywords: 42.60 ; 82.65 ; 73.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Continuous wave laser radiation from an argonion laser in the wavelength range 275–330 nm can be used to etch polyethylene terephthalate (PET) films with as little thermal damage as from a pulsed, ultraviolet laser (248 nm or 308 nm) provided the beam is focussed to a spot of 10–100 kW/cm2 of power density and is moved over the surface at speeds at which the transit time over its own diameter (which can be looked upon as a “pulse width”) is on the order of 10–200 μs. In contrast to results which had been obtained previously on the photokinetic etching of polyimide and doped polymethyl methacrylate films under similar conditions, the sensitivity of PET to etching is 〉5-fold greater than either of these polymers and increases steadily with increasing pulse width. There is lateral thermal damage as the pulse widths increase to 〉200 μs. The material that is removed is vaporized in part. More than 20% is probably ejected in a molten state and resolidifies at the edge of the cut. There is no acoustic report similar to that seen in ablative photodecomposition. The process appears to be largely thermal in nature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    ISSN: 1432-0630
    Keywords: 71.55 ; 72.40 ; 76.30.Da ; 78.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract On the basis of a previous identification of paramagnetic defects in nominally undoped as grown BaTiO3 single crystals, we have investigated the changes of the concentrations of these centers and their optical absorptions under illumination with light of varying wavelengths. The most pronounced charge transfers occur by hole ionization of Fe4+ and — to a lesser extent — of Cr5+ and Cr4+. At low temperatures the created holes are trapped in the form of O−-ions next to Al3+ or unknown acceptor defects. Corresponding Fe4+ and O− absorptions have been identified.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 55 (1992), S. 391-392 
    ISSN: 1432-0630
    Keywords: 42.60 ; 61.40 ; 68.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The adhesion-force of thin metal films on PET foils can be significantly improved by UV excimer-laser irradiation of the polymer surface prior to metal deposition. The laser fluences required are well below the ablation threshold.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 55 (1992), S. 30-32 
    ISSN: 1432-0630
    Keywords: 42.65 ; 42.40 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Using a ps-transient grating technique the contribution of the ps-photorefractive effect to the first-order probe-beam diffraction signal has been studied in CdTe at 1 μm investigating diffraction kinetics at different sample orientations in the thin grating regime. A fast photorefractive grating formation time during the pump pulses and a characteristic decay time of 600 ps, shorter than the free-carrier lifetime, have been observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 53 (1991), S. 194-197 
    ISSN: 1432-0630
    Keywords: 72.40 ; 72.20 ; 85.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A transient negative photoconductivity phenomenon observed in silicon doped with gold atoms has been investigated. On the basis of the trapping of photo-excited carriers into two deep levels of gold atoms, a model for the occurrence of transient negative photoconductivity is proposed and related qualitatively to some experimental results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 53 (1991), S. 81-86 
    ISSN: 1432-0630
    Keywords: 61.70 ; 72.40 ; 78.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Measurements of photoconductivity and light-induced absorption in KNbO3: Fe are performed at different light intensities and crystal temperatures. The results are interpreted in terms of a two-center charge transport model. Different model parameters may be evaluated from the experimental data. A complete set of parameters is suggested explaining the dependences of photoconductivity and light-induced absorption on light intensity and temperature for the KNbO3: Fe crystal investigated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 53 (1991), S. 330-331 
    ISSN: 1432-0630
    Keywords: 42.60 ; 61.40 ; 68.35
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Structure formation observed in UV-laser ablated poly-ethylene-terephthalate (PET) foils can uniquely be assigned to mechanical and thermal pretreatments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 51 (1990), S. 13-17 
    ISSN: 1432-0630
    Keywords: 61.70 ; 72.40 ; 78.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A charge transport model including deep and shallow traps explains both the nonlinear relation between photoconductivity and light intensity and the light-induced absorption in BaTiO3. A correlation between measurements of photoconductivity and light-induced absorption as a function of temperature yields parameters for the shallow center, among them thermal activation energy and generation rate.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 50 (1990), S. 131-139 
    ISSN: 1432-0630
    Keywords: 81.60 ; 82.65 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The present status of experimental and theoretical work on continuous wave laser-assisted reaction of metals with oxygen is presented. Differences between this and normal isothermal oxidation of metals are emphasized. Available theoretical models are discussed. They deal with roles of thermal history, feedback effects between optical absorption and reaction rate. The nature of so-called “non-purely thermal” effects is discussed. Hints for further research are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1432-0630
    Keywords: 61.70 ; 78.30 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Shallow thermal donors are electrically active oxygen-related thermally formed defects observed in oxygen-rich silicon annealed between 300 ° and 600 ° C. Seven donors have been identified with an average central-cell correction of only 5 meV. In view of their molecule-like nature this close agreement to the effective mass theory prediction for a hydrogen-like donor in silicon is of interest. It is shown that these centres are not correlated to the residual impurities phosphorus and boron but rather to the presence of nitrogen. Nitrogen-doped oxygen-rich samples show increased shallow thermal donor growth and a reduction in the growth of other oxygen-related donors in comparison to normally nitrogen-undoped oxygen-rich samples. A reduction in shallow thermal donor concentration at high nitrogen concentrations is reported.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 48 (1989), S. 237-240 
    ISSN: 1432-0630
    Keywords: 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This study presents a simulation that is used to determine the sensitivity of the phase shift analysis of the modulated photocurrent method to the differences in the fine scale structures in the density of states (DOS) distributions. Four DOS distributions are considered and the expected data are obtained. The results show that the modulated photocurrent method is very sensitive to such fine features in the DOS distributions. A comparison is also made with the sensitivity of other techniques commonly used in the determination of the DOS profiles.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 49 (1989), S. 165-169 
    ISSN: 1432-0630
    Keywords: 72.20 ; 72.40 ; 73.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This paper is concerned with the optimization of growth conditions for a-Si1-x Ge x :H alloys. It is shown that H-dilution of source gases selectively improves the band transport of electrons without significantly affecting the recombination center density or the band transport of holes. It is further shown that the beneficial effects of H-dilution are most pronounced in alloys with comparable densities of Si and Ge.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 49 (1989), S. 189-197 
    ISSN: 1432-0630
    Keywords: 42.60 ; 81.10 ; 82.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The photolytic laser chemical vapor deposition (LCVD) rate of platinum from its bishexafluoroacetylacetonate precurser has been measured in situ and in real time. Optical transmission of the 350 nm photolysis light through the deposited platinum film and a transparent glass substrate is monitored and analysed in detail. From these measurements, as well as measurements of the reflected light, the fraction of the laser beam power absorbed in the metal film is found. The latter allows a simple estimate of the laser-induced temperature rise at the metal surface. It is shown that even rather small temperature increases of the order of several tens of degrees centigrade can completely change the photolysis mechanism and hence drastically influence the photolytic LCVD rate. A simple modification of Lax's model, in which a temperature dependent thermal conductivity of the substrate is introduced, is used to describe the laser-induced heating of a strongly absorbing thin metal film on a glass substrate.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 48 (1989), S. 527-541 
    ISSN: 1432-0630
    Keywords: 74.70 ; 42.60 ; 81.10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The use of lasers in the formation and surface processing of high-temperature superconductors (HTS) is reviewed. Presently, thin film fabrication by reactive laser sputtering, and surface patterning by laser-induced reduction/metallization and ablation are the most promising applications. The great majority of the investigations have been performed for Y-Ba-Cu-O.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    ISSN: 1432-0630
    Keywords: 72.20 ; 72.40 ; 72.80J ; 77.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract ac measurements (1 Hz–10 kHz) have been carried out on a Pb2CrO5 ceramic sample (with surface electrodes) at room temperature as a function of voltage and intensity of visible light illuminating the sample. Cole-Cole complex impedance plots show that the electrical behaviour of Pb2CrO5 is strongly modified when the sample is illuminated. The bulk conductance of the sample is found to increase with increasing light intensity indicating that this dielectric material becomes semiconducting due to the photogeneration of free charge carriers in the conduction band. The dielectric constant of the sample is enhanced by illumination probably due to light-dependent space charge effects in a manner where the dielectric's relaxation time (τ=RC=0.7 ms) remains constant with light intensity. On the other hand, both the bulk conductance and geometrical capacitance of the sample have been found to be almost independent of the applied voltage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 48 (1989), S. 517-520 
    ISSN: 1432-0630
    Keywords: 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract One of the major problems of the method of phase shift analysis of modulated photocurrent for studying the density of states in the energy gap of amorphous semiconductors has been the determination of the energy scale corresponding to this DOS profile. This study presents a new way of dealing with this problem. This new method is especially useful in the case where the DOS profile lacks a characteristic peak. A computer analysis is used to confirm the validity of this method and to demonstrate how it can be used.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 48 (1989), S. 273-276 
    ISSN: 1432-0630
    Keywords: 07.20 ; 42.60 ; 44.50 ; 78.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A phosphor with temperature-dependent lifetime has been used to measure the temperature distribution produced by laser heating of a thin film surface. A gold thin film deposited on a quartz substrate is coated with ∼40 μm film of the phosphor material. A cw argon ion laser (476 nm) beam is split into two beams, with the more intense beam focused to 15 μm (1/e2 radius) to heat the film through the quartz substrate. The weaker probe beam is chopped and focused tightly using a microscope objective to excite the phosphor from the other side. The spatial variation in lifetime, and hence the temperature distribution, is obtained by scanning the probe beam over the heated region. The temperature distribution measured for different film thickness's is compared with calculations using a finite element model. The calculated temperatures at the gold surface near the laser beam are higher than the experimentally measured values, and agree only when the heat-sinking effect of the phosphor material is taken into account. The results suggest that a phosphor layer thinner than a micron will be required (for 15 μm laser spot size) so as not to perturb the temperature of the gold layer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 49 (1989), S. 221-223 
    ISSN: 1432-0630
    Keywords: 74.70 ; 42.60 ; 81.10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Superconducting films of Bi-Sr-Ca-Cu-O on (100) MgO substrates have been fabricated by XeCl-excimer-laser sputtering from ceramic targets of Bi2.5Sr2Ca2Cu3Oy in O2 atmosphere. The films were polycrystalline with the c-axis (30.80±0.02Å) preferably oriented normal to the substrate surface. Without post-annealing the films showed metallic resistance behavior with zero resistance temperatures of up to Tc(0) }- 79 K. The critical current density of the films had values of up to jc(50K)}- 104 A/cm2.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 221-224 
    ISSN: 1432-0630
    Keywords: 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract For the determination of the density of states in the mobility gap of amorphous semiconductors using the “phase shift analysis of modulated photocurrent,” this paper suggests that making use of the magnitude of the induced photocurrent helps to remove arbitrariness in the energy scale. The working equations for the density of states and the corresponding energy position are expressed in terms of the intensity of the photocurrent. A simulation is made for a specific distribution, to investigate the validity of the procedure. The results show that the profile of the energetic distribution of localized states and the exact energy position of each state are consistent with the original distribution considered.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 47 (1988), S. 313-316 
    ISSN: 1432-0630
    Keywords: 81.60 ; 82.65 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The processes leading to the control of the lateral dimension of laser-assisted oxidation of Zn films on glass are examined. It is shown that it is determined by negative feedback between temperature and optical absorption.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 47 (1988), S. 377-386 
    ISSN: 1432-0630
    Keywords: 81.60 ; 82.65 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Laser-induced chemical etching of (100) Si in Cl2 atmosphere has been investigated using a combined laser-beam irradiation scheme. 308 nm XeCl excimer laser radiation at parallel incidence has been used to exclusively generate Cl atoms in the gas phase above the Si surface. Additionally, 647.1 nm Kr+ laser radiation at perpendicular incidence has been used to exclusively generate photocarriers within the Si surface. The Cl atom concentration was determined — independently — from both the observed chemiluminescence following the Cl-Cl atom recombination, and from numerical calculations. The etch rateW observed on the Si surface was found to be directly proportional to the Cl atom concentration in the gas phase, and it increases sublinearly with the Kr+ laser powerP according toW∞P 0.7.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 1432-0630
    Keywords: 72.40 ; 73.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Excess charge carrier kinetics in moderately doped pSi wafers were investigated with a contactless transient photoconductivity method, i.e. the time-resolved microwave conductivity (TRMC) method. The surface structure of the wafers was changed by etching and polishing, the volume structure by irradiation with high-energy electrons. Comparison of the photoconductivity decay after excitation by strongly absorbed light and by weakly absorbed light was used to distinguish between surface and volume decay processes. The experimental results deviate from predictions based on a linear surface decay rate. These results are discussed and suggestions are made for the use of transient photoconductivity measurements to characterize semiconductor wafers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 289-292 
    ISSN: 1432-0630
    Keywords: 42.60 ; 82.65 ; 73.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Although polymethyl methacrylate (PMMA) is essentially transparent to light of 308 or 351 nm, it can be made sensitive to photoablation and etching by excimer laser pulses (20 ns half-width) of those wavelengths by the introduction of an organic dopant. The dopant (trade name=Tinuvin*) is actually a quencher of the first electronic excited state of PMMA and is therefore used commercially to stabilize the polymer against photodegradation. Laser etching of Tinuvin-doped PMMA can be shown to be a photochemical process in which the Tinuvin decomposes by the absorption of two or more photons and causes the ablation of the surrounding polymer.*[2-(2′-hydroxy-3′,5′-diisopentyl-phenyl) benzotriazole].
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 301-304 
    ISSN: 1432-0630
    Keywords: 42.60 ; 82.50N ; 85.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract KrF laser etching of GaAs in Cl2 and O3 gas ambients by direct laser illumination is reported. The etch depth per pulse in Cl2 was found to be linear versus the laser fluence on the sample in the 0.2–1.1 J/cm2 range. It increased as a function of the Cl2 pressure up to 6 Torr and slightly decreased for pressures above this value. It also decreased as a function of the laser repetition rate. Very smoothly etched surfaces were obtained after irradiation using the Cl2 and O3 etching gases. Auger analysis of the etched GaAs surfaces shows almost no traces of chlorine after etching in Cl2, whereas a thick oxide layer of about 1500 Å thickness was found after etching in ozone.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 293-299 
    ISSN: 1432-0630
    Keywords: 81.60 ; 82.65 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Laser-induced chemical etching of single-crystalline (100) Si in Cl2 atmosphere has been investigated for continuous Ar+ and Kr+ laser irradiation at around 351 nm, and at 457.9, 488.0, 514.5, and 647.1 nm. For laser irradiances below 105 W/cm2 the etching mechanism is non-thermal, and is based on photo-generated electron-hole pairs within the Si surface and Cl atoms produced within the gas phase. The experimental results are compared with model calculations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 46 (1988), S. 331-334 
    ISSN: 1432-0630
    Keywords: 74.70V ; 42.60 ; 82.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Investigations on the laser-induced oxidation of YBa2Cu3O6 are presented. Here, the oxygen content of the material is locally increased by laser-induced heating under cw Ar+ or Kr+ laser irradiation in 02 atmosphere. The technique permits direct-writing of superconducting patterns into the semiconducting sample surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 46 (1988), S. 285-290 
    ISSN: 1432-0630
    Keywords: 42.60 ; 81.10 ; 85.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Microscopic ohmic contacts are made by laser chemical vapor deposition of platinum on a Pyrex substrate. The electrical conductivity of the deposited metal stripes is measured as a function of the laser power, the writing speed, and the organometallic vapor pressure. The latter appears to be the key parameter for producing contacts with low resistance at high writing speeds. Even on these transparent substrates there is no apparent advantage in using light at 350 nm, where photolysis may in principle play a significant role, over using visible light where photolysis is not effective.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 46 (1988), S. 331-334 
    ISSN: 1432-0630
    Keywords: 74.70V ; 42.60 ; 82.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Investigations on the laser-induced oxidation of YBa2Cu3O6 are presented. Here, the oxygen content of the material is locally increased by laser-induced heating under cw Ar+ or Kr+ laser irradiation in O2 atmosphere. The technique permits direct-writing of superconducting patterns into the semiconducting sample surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 313-316 
    ISSN: 1432-0630
    Keywords: 42.60 ; 74 ; 82.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The first investigations on the laser-induced reduction of YBa2Cu3O7−x are presented. Here, the oxygen content of the material is diminished by local heating under cw Kr+ laser irradiation in H2 atmosphere. The technique permits the superconducting properties of the material to be locally changed or destroyed. Laser-induced surface metallization may be useful for the electroding of such materials.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 355-360 
    ISSN: 1432-0630
    Keywords: 81.10 ; 68.55 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Diamond-like carbon thin films were prepared by pulsed-laser evaporation. In this method a carbon target was irradiated by a XeCl laser with a power density of 3×108 W/cm2 and carbon atoms, together with a small number of ions, were produced. Deposition rates and film properties changed sensitively with substrate temperature. The films deposited at 50°C were diamond-like, having reasonable hardness, high refractive index (2.1–2.2 at 633 nm), optical transparency in the infrared, electrical resistivity of 108 Ω cm and chemical inertness (no dissolution in a HF∶HNO3 solution). The band gap measured from optical absorption was 1.4 eV. Raman spectrum and infrared absorption, whose features varied with the substrate temperature, were also measured. The films were amorphous and no crystallinity was observed, as confirmed by x-ray diffraction, transmission electron diffraction and Raman spectroscopy. Hydrogen atoms were incorporated in the films with a typical H/C ratio of 0.3. The application of a negative bias to the substrate modified the deposition due to the presence of ions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 337-343 
    ISSN: 1432-0630
    Keywords: 42.60 ; 81.10 ; 82.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The rate of cwphotolytic laser chemical vapor deposition (LCVD) of platinum is measured for λ≈350 nm as a function of the light intensity and the metalorganic vapor pressure. The growth of the metal films is studied in situ and in real time by monitoring their optical transmission. At low intensities the transmitted light decreases monotonically with time, and the LCVD process is photolytic with its rate limiting step in the surface adlayer. At higher intensities we observe two distinct time domains: Relatively slow initial photolytic deposition with its rate limiting step in the gas phase, which is followed by much faster pyrolytic LCVD. An improved method for distinguishing between adlayer and gas-phase limiting processes is demonstrated. These observations are confirmed by studying the photolytic deposition rates while varying the thickness of the adlayer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 47 (1988), S. 103-104 
    ISSN: 1432-0630
    Keywords: 42.60 ; 74 ; 82.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The ablation of ceramic Bi-Ca-Sr-Cu-O by XeCl-excimer-laser projection has been investigated. In both air and vacuum, etching commences at about 2.4 J/cm2 and then increases with fluence within the regime investigated (Φ 〈) 20 J/cm2). At 10 J/cm2 the respective etch rates are around 1 μm/pulse and 1.6 μm/pulse.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 47 (1988), S. 193-197 
    ISSN: 1432-0630
    Keywords: 68.55 ; 72.40 ; 81.15
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Hydrogenated amorphous silicon films have been prepared by primary ion beam deposition with a new electrodeless rf ion source. The design of the ion source is described. The composition of the a-Si:H films has been determined by Rutherford backscattering, and the photoconductivity by the constant photocurrent method (CPM). The best a-Si:H films show photoconductivities of 5×10−5 (Ω cm)−1. The deposition rates were between 0.7 and 1.2 nm s−1.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 46 (1988), S. 285-290 
    ISSN: 1432-0630
    Keywords: 42.60 ; 81.10 ; 85.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Microscopic ohmic contacts are made by laser chemical vapor deposition of platinum on a Pyrex substrate. The electrical conductivity of the deposited metal stripes is measured as a function of the laser power, the writing speed, and the organometallic vapor pressure. The latter appears to be the key parameter for producing contacts with low resistance at high writing speeds. Even on these transparent substrates there is no apparent advantage in using light at 350 nm, where photolysis may in principle play a significant role, over using visible light where photolysis is not effective.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 47 (1988), S. 377-386 
    ISSN: 1432-0630
    Keywords: 81.60 ; 82.65 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Laser-induced chemical etching of (100) Si in Cl2 atmosphere has been investigated using a combined laser-beam irradiation scheme. 308 nm XeCl excimer laser radiation at parallel incidence has been used to exclusively generate Cl atoms in the gas phase above the Si surface. Additionally, 647.1 nm Kr+ laser radiation at perpendicular incidence has been used to exclusively generate photocarriers within the Si surface. The Cl atom concentration was determined — independently — from both the observed chemiluminescence following the Cl-Cl atom recombination, and from numerical calculations. The etch rateW observed on the Si surface was found to be directly proportional to the Cl atom concentration in the gas phase, and it increases sublinearly with the Kr+ laser powerP according toW∞P 0.7.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 43 (1987), S. 205-208 
    ISSN: 1432-0630
    Keywords: 72.40 ; 72.20 ; 85.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A transient negative photoconductivity phenomenon observed in silicon doped with gold atoms by an appropriate diffusion condition has been investigated. The transient negative photoconductivity could be observed with a diode doped with gold atoms under intrinsic light-pulse illumination. In the recovery process of the transient negative photoconductivity to a steady-state dark level, two kind of time constants were observed, which may be related with the emission of electrons from gold level. A dependence of the magnitude of the peak value on the ambient temperature was observed; a qualitative explanation is given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 42 (1987), S. 173-177 
    ISSN: 1432-0630
    Keywords: 72.15 ; 72.40 ; 78.55 ; 79.20 ; 85.40 ; 85.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A superlattice avalanche photodiode using III–V materials is expected to be used in long-distance fiberoptic communication systems in the 1.3 to 1.55 μm wavelength range. Theoretical studies have been made on the effective ionization rates of electrons and holes of the device, I–V characteristic and the frequency response characteristic of the Al x Ga1−x As/GaAs superlattice p+-i-n+ structure. It is observed that theα/β ratio of the device increases with the field and the bandwidth of the response curve increases with decrease in the dc multiplication gain.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 42 (1987), S. 311-315 
    ISSN: 1432-0630
    Keywords: 70.20 ; 72.40 ; 85.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Avalanche photodetectors are very important solid-state detectors currently used in long-distance and wide-band optical communication systems, due to their faster speed of response compared to other solid-state photodiodes. Furthermore, it has been found that by using heterostructures one can improve both multiplication gain and quantum efficiency of such a device. DOVATT is a heterojunction impatt device in which there is one avalanche zone followed by two drift zones at different scattering limited velocities. The device is very useful for generation of high power in the X-band. The present paper examines the effect of optical radiation on such a device. Studies have been made on the frequency-response characteristics of the device. The results show that the device has the potentiality of becoming a powerful photodetector in optical communication systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 44 (1987), S. 245-247 
    ISSN: 1432-0630
    Keywords: 61.70T ; 71.55F ; 72.40 ; 78.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Photoionization of the DX center in Si-doped A10.33Ga0.67As has been studied by means of photoconductivity. The optical cross-sectionσ nd 0 shows a threshold atħω=200 meV and relative maxima (shoulders) around 400, 600, 950, and 1700 meV. The results throw doubt on the validity of the large lattice relaxation model, generally accepted for this class of centers. They can be well accounted for by the small relaxation model, recently proposed by the authors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 44 (1987), S. 361-364 
    ISSN: 1432-0630
    Keywords: 72.40 ; 78.55 ; 85.30 ; 85.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Carrier frequency-dependent intrinsic parameters of an ion-implanted silicon photo-MESFET have been analysed theoretically. The internal gate source capacitanceC gs is found to increase with increasing carrier frequency under the normally OFF condition and the change is small under the normally ON condition. Also, the internal drain-source resistanceR ds increases with frequency at a fixed flux density and wavelength of operation. The ion-implanted photo-MESFET could become useful as optically controlled switching device in digital circuits.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    ISSN: 1432-0630
    Keywords: 81.10 ; 85.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The laser chemical vapor deposition of platinum from its bishexafluoroacetylacetonate derivative is studied with a cw argon ion laser at 458 and 514 nm. The height, the width, as well as the electrical conductivity of the deposited stripes are reported as a function of the vapor pressure of the metalorganic precurser, the laser intensity, and the writing speed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    ISSN: 1432-0630
    Keywords: 77.40 ; 72.40 ; 77.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The electrical and dielectric properties of mercuric iodide were studied at room temperature under various intensities and colours of light in the frequency range 1 Hz–10 kHz. In the high-frequency region (〉40 Hz), the real part of the dielectric constant (ɛ′) is almost constant with frequency (f), colour and intensity of light. At lower frequencies,ɛ′ varies nearly as 1/f and monotonically increases with intensity (I) of the yellow (or green) light, whereas it is almost constant with red light intensity. This behaviour is discussed in the view of the different polarization contributions. The imaginary part of the dielectric constant (ɛ″) was found to vary as 1/f over the frequency range studied. This behaviour was observed whether the crystal was in dark or illuminated implying that the roomtemperature ac dark- or photo-conductivity (σ) is independent of frequency. The observed variation ofσ with intensity of yellow (or green) light was found to follow anI 1/2 dependence and a weaker dependence for the red light. the red light. The conductivity behaviour is discussed in the view of the current theories.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 43 (1987), S. 227-232 
    ISSN: 1432-0630
    Keywords: 81.60 ; 82.65 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Chemical etching of single-crystalline (100)Si induced by pulsed laser irradiation at 308, 423, and 583 nm has been investigated as a function of the laser fluence and C12 pressure. Without laser-induced surface melting, etching requires Cl radicals which are produced only at laser wavelengths below 500 nm. With low laser fluences (Φ(308 nm)〈100 mJ/cm2) etching is non-thermal and based on direct interactions between photocarriers and Cl radicals. For fluences which induce surface melting (Φ(308 nm)〉440 mJ/cm2) etching is thermally activated. In the intermediate region both thermal and non-thermal mechanisms contribute to the etch rate.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 40 (1986), S. 235-239 
    ISSN: 1432-0630
    Keywords: 42.60 ; 81.30 ; 82.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The laser-induced etching of ceramic PbTi1−xZrxO3 in a hydrogen atmosphere and in air has been investigated. Visible Ar+ and Kr+ laser radiation was employed in most of the experiments. In H2 atmosphere, regular patterning of the ceramic is possible. Average etch rates reach up to about 250 μm/s.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1432-0630
    Keywords: 42.70 ; 42.60 ; 61.80 ; 68.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We report on experimental data of chemical compounds formed in the damaged area at the surface of certain optical ZnSe windows subjected to multi-pulse microsecond pulsed TEA-CO2 laser irradiation in air. The results are analysed from the viewpoint of implication of the oxidation process activated under the action of CO2-laser power in plasma initiation and evolution of surface damage process.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 39 (1986), S. 291-296 
    ISSN: 1432-0630
    Keywords: 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract p-Type Ge is investigated as a photon-drag detector for high-power pulsed CO2 laser, using 3-samples of different dimensions and resistivities. Nonlinear behaviour of the photon-drag effect is observed. This phenomena could be accounted for by taking into consideration the decrease of absorption and the increase of resistivity instantaneously at the moment of interaction, rather than the effect of multireflection. The observed saturation at intensities higher than 30 MW/cm2 could be due to multireflection since its role increases at high intensities. Using the quantum mechanical model with the above considerations it was possible to obtain good agreement to the measured results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1432-0630
    Keywords: 86.30 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We have made theoretical studies on the limitation of the open-circuit voltageV oc of a hydrogenated amorphous silicon (a-Si:H) p-i-n type solar cell. The effects of the tail states in the a-Si:H i layer and of the interface recombination are discussed in detail. The opencircuit voltage increases when the distribution of the tail states is sharp and/or the capture cross sections of these states are small. This is because the recombination rate of photogenerated carriers and/or the density of space charge due to trapped carriers in these states become low in these conditions. These effects of the tail states on the value ofV oc become pronounced when the built-in potential of the p-i-n junction is high. The decrease in the effective recombination velocity of carriers at the p/i and n/i interfaces results in an increase ofV oc. This increase becomes remarkable when the effects of the tail states on the value ofV oc are small. Both the sharp distribution of tail states and the small value of the interface recombination velocity are necessary to increase considerably the value ofV oc. We show the conditions of the material parameters necessary to obtain an open-circuit voltage of 1.0 V.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 40 (1986), S. 29-36 
    ISSN: 1432-0630
    Keywords: 42.60 ; 64 ; 68.20 ; 81.10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This paper deals with selfsustaining crystallization processes, the so-called explosive crystallization, in silicon produced by short temperature pulses. By this, crystalline Si layers can be generated on amorphous substrates, e.g. on SiO2, at which liquid and solid-state crystallization processes can take place. Emphasis will be given to the liquid-phase explosive crystallization processes. Here, the transformation of amorphous into crystalline silicon occurs through two coupled laterally moving interfaces, amorphous-liquid and liquid-crystalline. Using an experimental equipment existing of 3 synchronized lasers supplying the temperature pulse for the ignition, the spreading out and stopping of the laterally moving interfaces, in connection with time-resolved measurements of the reflectivity by a laser test beam, information about the characteristic parameters as the velocity of the process, the crystallized area and the course of the crystallization front will be obtained. The crystalline structure was investigated by optical and transmission-electron micrography. The main results are: the crystallization fronts move radially from the ignition point with a velocity of about 15 m/s, crystalline laminae grow preferentially in 〈110〉 direction over a distance of more than 100 μm, areas of some millimeters in diameter can be crystallized and the quality of the crystallized layers essentially depends on the “amorphousness” of the virgin layer and the preparation method. The experimental results are in good agreement with theoretical predictions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 41 (1986), S. 331-334 
    ISSN: 1432-0630
    Keywords: 82.65 ; 42.60 ; 81.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Hot pressed, optically transparent ferroelectric ceramics of lanthanum modified lead zirconate titanate (PLZT) have been locally reduced and metallized by means of ultraviolet Kr+ laser irradiation in a hydrogen atmosphere. The technique allows maskless single-step metallic patterning of the material.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    ISSN: 1432-0630
    Keywords: 68.55 ; 42.60 ; 82.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A theoretical analysis of and experimental observations on a parallel incident laser-induced deposition rate are reported. Our theory predicts that the maximum deposition rate depends on the photo-traveling length, the scattering cross section of the reactant gases and their partial pressure. This result is applied to SiO2 deposition using monosilane and nitrous oxide for reactant gases, and is compared with experimental results. We show that the deposition rate of SiO2 films as a function of the incident light power and the partial pressure of reactant gases predicted by the present theory well explains our experimental results. A supply-limitation phenomenon of the reactant gases and a method of estimating deposition efficiencies are also discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 37 (1985), S. 153-164 
    ISSN: 1432-0630
    Keywords: 86.30 ; 72.40 ; 73.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We have made theoretical studies on the trapping and recombination of photogenerated carriers in hydrogenated amorphous silicon (a-Si∶H) p-i-n solar cells. We discuss in detail the following points: 1) The limitations of the assumptions in the previous analysis. It has been clarified that the single-level Shockley-Read-Hall model for carrier recombination and the treatment of trap occupation in terms of quasi-Fermi levels are inadequate for exact analysis. 2) The superlinear dependence of carrier recombination rate on the free-carrier density which can explain the enhancement of photo-induced changes ina-Si∶H under high intensity light. 3) The estimation of capture cross section of the tail states ina-Si∶H. We show that the charged and neutral tail states have rather small capture cross sections of less than 10−16 cm2 and of less than 10−19 cm2, respectively. 4) The effect of the recombination of photogenerated (PG) carriers at the p/i and the n/i interfaces. We estimate the recombination velocityS of PG carriers at these interfaces to be about 103 cm/s. It has been also clarified that the decrease inS is effective to improve the cell performance, especially the open circuit voltage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    ISSN: 1432-0630
    Keywords: 42.60 ; 61.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A cw CO2 laser, coupled with an astigmatism free beam focussing mirrors arrangement is used for processing a brittle plastic, CR-39 without producing cracks, vents or chips. The processing is based on the formation of volatile products of laser-induced decomposition in the plastic. Threshold fluence for the decomposition (found to be independent of the power density and beam residence time) in CR-39 atλ=10.6μm is determined to be 25 J cm−2 and the decomposition threshold power density for cw irradiation 2.1±0.5 W cm−2. The depth and width of the tapered laser processed region are observed to increase with power density and beam residence time. The widths attain a steady state value of ∼ 1 mm at beam residence time above 65 ms, for a fixed power density (2.5×104 W cm−2) and sheet thickness (250 μm). Taper angle of the edges decreases with increasing power density and/or beam residence time. The heat affected zone (measured in crossed polarisers) around the processed region is found to extend with increasing beam residence time but remains unaffected on changing power density. The results are discussed in terms of the optical and thermophysical properties of CR-39 and the parameters of the interacting laser beam.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    ISSN: 1432-0630
    Keywords: 73.60 ; 72.40 ; 78.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Amorphous Si1−xCx: H thin films were prepared by the rf magnetron sputtering method using a composite target of silicon and graphite. The dependence of the optical, structural, electrical, and optoelectronic properties on the carbon contentx was investigated, by measuring the optical absorption spectra, ir spectra, dark conductivity, photoconductivity and ESCA spectra. The optical gap was found to be unchanged with increasingx below about 0.6, in spite of the increase in the amount of the SiC bond. This is considered to be due to the formation of the carbon clusters. It is found that the photosensitivity shows a maximum at aboutx = 0.2, and is about one order of magnitude larger than the film withx = 0. This is related to the decrease in the dark conductivity, which is ascribed both to the formation of the SiC bond and to the reorganization of the defect-rich structure of sputter-deposited amorphous Si by the addition of about 20% carbon. The photoconductive effect was gradually lost in the range ofx above 0.6. In this range, the optical gap increases rapidly owing to the rapid increase of the SiC bond.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...