ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 6146-6149 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The crystallization of a mechanically alloyed Sm-Fe alloy was investigated. The results show that the Sm-Fe alloy prepared by mechanical alloying consists of amorphous Sm-Fe phase and crystalline α-Fe phase. The composition of the alloy is inhomogeneous, i.e., the surface of the as-milled powder is relatively poor in iron. The crystallization process involves the long-range diffusion of iron atoms and solid state reaction. After proper crystallization, the as-milled powder transforms into a Sm2Fe17 phase completely; no distinguishable crystalline α-Fe phase can be found. A metastable phase, which may be a Sm2Fe17 phase with the structure of hexagonal Th2Ni17 type, appears during the crystallization process.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 5662-5665 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two sharp bands at ∼1350 and ∼1600 cm−1 were observed in the Raman spectra of carbon-implanted GaN after postimplantation annealing treatments. The intensities of these two bands increased while their full widths at half maximum decreased with increasing annealing temperature. The observation of these two bands indicates the formation of microcrystalline graphite in C-implanted GaN. Hall measurements demonstrated that some dispersed C in GaN acted as acceptors and played a role in reducing electron concentration and Hall mobility. The facts that in 1100 °C furnace annealing the intensities of these two Raman peaks decreased rapidly to zero and the resistivity increased by 3 orders of magnitude indicate the dissolution of microcrystalline graphite at this temperature. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 6935-6937 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Solid C60/n-GaN heterojunctions have been fabricated and their electrical properties have been studied. It has been found that the heterojunction is a strongly rectifying contact with a rectification ratio greater than 106 and with an ideality factor close to 1. The current–temperature measurement shows an exponential decrease of current with increasing reciprocal temperature, from which the effective barrier height is determined to be 0.535 eV. The series resistance measured decreases with increasing forward voltage and finally tends to be constant. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 4917-4921 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have performed outgoing resonant Raman scattering and photoluminescence measurements on as-grown, Be- and C-implanted GaN in the temperature range of 77–330 K. In implanted GaN after postimplantation annealing at 1100 °C, the A1(LO) multiphonons up to the seventh order were observed with the very strong four longitudinal optical (LO) and five LO modes at ∼2955 and ∼3690 cm−1, respectively, showing extraordinary resonance behavior. With the sample temperature, these two modes significantly decreased and increased in intensity, respectively. The phenomenon is attributed to the variation of resonant conditions due to the shift of the band gap energy. Meanwhile, the combination of E2(high) and quasi-LO phonons was strongly enhanced by quasi-LO phonon involvement and thus the corresponding overtones can be clearly observed even up to the sixth order (m=6). The mechanisms that such strong outgoing multiphonon resonance Raman scattering occurred to implanted GaN instead of high-quality as-grown GaN samples can be attributed to the strong Frohlich-induced scattering by LO phonons and exciton-mediated resonant Raman scattering with impurity inducement. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 2020-2024 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated three In1−xGaxAsyP1−y/InP p-i-n multiple quantum well (MQW) laser structures with different p-doping profiles using contactless electroreflectance (CER) and piezoreflectance (PZR). From the observed Franz–Keldysh oscillations originating in the i-InGaAsP regions, we have evaluated the electric field and hence the amount of p-dopant interdiffusion, which is in agreement with secondary ion mass spectrometry measurements. The CER/PZR spectra from the MQWs makes it possible to evaluate the parameters of these regions of the samples. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 6184-6188 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An external linear electro-optic measuring system based on a poled polymer asymmetric Fabry–Perot multiple reflection film has been built, and the electric signals propagating on an indium tin oxide coplanar strip transmission line have been successfully measured. The nonlinear polymer spin coated on the high-reflectivity glass substrate was corona poled, thus an asymmetric Fabry–Perot film was fabricated based on polymer reflectivity and high reflectivity glass. The film standing-free technique and reflective configuration were adopted in this system. The principle of the system was analyzed by multiple reflection and index ellipsoid methods. The voltage sensitivity about 5 mv/Hz was obtained as 1 kHz sine input electric signals propagating on coplanar electrodes. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 1340-1342 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: ZnSe self-organized dot structures on ZnS thin films were fabricated by the molecular beam epitaxy technique. In situ reflection high-energy electron diffraction studies reveal that growth interruption is required for the formation of the dot structure. Atomic force microscopy (AFM) images of the dots taken within the same day of growth reveal that the dot density increases with increasing ZnSe coverage. A density of 18 μm−2 was achieved with a coverage of 8.0 ZnSe monolayers. AFM images taken at later times (up to six months later) show ripening effects. The average dot size measured at various times after growth is consistent with the prediction of the Ostwald ripening model with a growth time constant of 4±1 days for the structure with a coverage of 8.0 ZnSe monolayers. The dot size and density in the fully ripened state are essentially independent of the initial ZnSe coverage. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 2229-2235 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using contactless electroreflectance we have characterized the complete potential profile of a pseudomorphic 0.98 μm InGaAs/GaAs/GaAlAs graded index of refraction separate confinement heterostructure (GRINSCH) laser fabricated by molecular beam epitaxy. Signals were detected from all three relevant portions of the sample. Comparison of the observed transitions from the InGaAs single quantum well (SQW) section with an envelope function calculation (including the effects of strain and electric field) made it possible to evaluate the In composition and width of the SQW. These values are in good agreement with the intended parameters. The energy of 11HH, the fundamental conduction to heavy-hole level (which is closely related to the lasing frequency) can easily be determined to less than ±1 meV at 300 K. From the period of the observed Franz–Keldysh oscillations (FKOs) originating in the GaAlAs GRINSCH region it was possible to directly evaluate the built-in electric field in the structure. We also present a general expression for FKOs in the presence of both electric fields (due to charge) and the "fields" (potential gradient) due to compositional grading. The temperature dependence (20 K〈T〈320 K) of quantum transitions from the InGaAs SQW has been evaluated. Our analysis has emphasized the 11HH transition because it can provide information on the operational temperature of the laser. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 4447-4453 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have derived expressions for the origins of the Franz–Keldysh oscillations (FKOs), observed in electromodulation, associated with the fields in the Ga1−xAlxAs emitter and GaAs collector regions of graded band gap heterojunction bipolar transistor structures. We show that while the latter FKOs are a measure of the maximum collector space charge field at the collector/base junction the former FKOs are determined by both the space-charge field and the "field" due to the grading in the emitter region. The special case of the abrupt emitter/base junction also is considered. Our expressions are general and can easily be applied to any graded (or abrupt) emitter structure. The results will be compared with experiment, including the photovoltaic effect. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 6430-6433 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Both Fourier transform infrared (FTIR) grazing incidence reflectivity and FTIR transmission methods have been used to study GaN films grown on α-Al2O3 (0001) substrates by atmospheric pressure metal-organic chemical vapor deposition and low pressure metal-organic chemical vapor deposition. The results show that in the frequency range from 400 to 3500 cm−1 the signal-to-noise ratio of the FTIR grazing incidence measurement is far higher than that of the FTIR transmission measurement. Some new vibrational structures appearing in the former measurement have been discussed. The features around 1460 and 1300 cm−1 are tentatively assigned to scissoring and wagging local vibrational modes of CH2 in GaN, respectively. © 1999 American Institute of Physics.
    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...