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  • 1
    ISSN: 1432-0630
    Keywords: 68.60 ; 81.15 ; 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 properties of Pulsed-Laser-Deposited Diamond-Like Carbon (PLD DLC) films are studied as functions of the power densityΦ and the wavelengthλ of the laser beam, and the incident angleϑ of the beam relative to the normal of the target surface. All the films have a similar structure consisting of graphite particulates embedded in a continuous matrix, so the macroscopic performance of the films is determined by the overall contributions of the particulates and the matrix. The use of higherΦ, shorterλ, or largerϑ leads to an enhancement of the diamond-like characteristics and a simultaneous increase of the particulate density. These two effects give opposite contributions to the electrical conductivityσ R, leading to the following results. (i) σR drops with increasingΦ in the lowΦ range (region I) due to the stronger diamond-like nature of the matrix, but increases sharply afterΦ has exceeded a thresholdΦ min as a result of the rapid increase in particulate density. (ii) In region I, the use of shorterλ or largerϑ leads to a more diamond-like matrix, and this overwhelms the degradation effect caused by the slight increase in particulate density. The samples thus become more insulating. In the highΦ region (region II), however, the use of shorterλ or largerϑ gives rise to higher particulate density, thereby increasing the electrical conductivity.
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 1956-1961 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Explosive-driven hemispherical-implosions were used to create high dynamic pressures (up to 13 GPa) and temperatures (up to 450 K) in an exploratory investigation of chemical reactions and diffusion processes in different materials subjected to extreme conditions. Diffusion coefficients as high as 200 cm2/s and chemical reaction rates as fast as 1000 mol/s (in a volume of 0.2 cm3) were inferred from shock experiments with carbontetrabromide (CBr4) and copper (Cu) powder mixtures. An outdiffusion of Ga from a single crystal GaAs substrate into a polycrystalline indium thin film deposited on it was also observed and confirmed by scanning electron microscopy and energy dispersive x-ray microanalysis.
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 2652-2654 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Carbon nitride (CNx) films were prepared by reactive pulsed laser deposition at nitrogen partial pressure PN2varying from 0 to 300 mTorr. It is found that the atomic fraction of nitrogen f in the films first increases with increasing PN2, reaches a maximum of 0.32 at PN2=100 mTorr, and then decreases to a saturated value of 0.26 at PN2(approximately-greater-than)200 mTorr. Because of the absence of energetic particles in reactive pulsed laser deposition, the limited nitrogen content cannot be attributed to preferential sputtering of nitrogen that is generally observed in particle-assisted deposition of CNx films. Infrared absorption experiments show the existence of C≡N bonds and graphitic sp2 bonds. The sp2 bonds become IR active because of symmetry breaking of graphitic rings as a consequence of nitrogen incorporation. CNx films deposited at low PN2 (e.g., 5 mTorr) are more graphitic than the diamondlike pure carbon sample deposited at PN2=0, so have a slightly narrower electron band gap Eopt and a significantly higher room-temperature electrical conductivity σR. At PN2(approximately-greater-than)200 mTorr, nitrogenation of the films is very pronounced, leading to a wide band gap (Eopt(approximately-greater-than)1.5 eV), long electron band tail (E0(approximately-greater-than)0.7 eV), and extremely low σR(〈1×10−13 Ω−1 cm−1). In addition, both the hardness and Young's modulus are greatly reduced, for example, from 41.3 and 285 GPa for the pure carbon sample to 1.2 and 23.8 GPa, respectively, at f=0.32. © 1995 American Institute of Physics.
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 245-247 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pulsed-laser deposition (PLD) of lead-zirconate-titanate [Pb(Zrx,Ti1−x)O3] (PZT) thin films under low ambient pressure has been investigated by studying the angular deposition distributions of the constituent elements of the films. Nonstoichiometric profiles are observed and a dip occurs near the target surface normal of the deposition profile of lead. Experimental results show that intrinsic resputtering of the film is important in the PLD process and is responsible for the anomalous distribution of lead. © 1995 American Institute of Physics.
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 3501-3503 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structural and mechanical properties of ion-beam deposited (B0.5−xSix)N0.5 films (0≤x≤0.5) were characterized by x-ray photoelectron spectroscopy, infrared absorption experiments, and nanoindentation tests. A single-layer BN film (x=0) has 70 vol. % in cubic phase (c-BN), and a hardness of 38 GPa. However, it peeled off very soon after deposition due to the high internal stress. If a buffer layer was deposited first, followed by a (B0.5−xSix)N0.5 film with x≈0.013, the whole configuration adhered very firmly to both quartz and silicon substrates. This improvement in adhesion was probably due to the formation of Si–N bonds, which served to release partly the stress inside the (B0.5−xSix)N0.5 films. Since the Si content was low, the film structure remained highly cubic, and there was no observable drop in hardness. For higher x, the cubic structure in (B0.5−xSix)N0.5 films disappeared rapidly and was replaced by a hexagonal structure. This structural change led to a rapid drop in hardness from 38 to 12 GPa. As x was further increased, more Si–N bonds were formed in the (B0.5−xSix)N0.5 layers. As a result, the hardness increased from the minimum value to a value ≈24 GPa. © 1996 American Institute of Physics.
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 2030-2032 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The angular distribution of lead in films deposited by pulsed laser irradiation of lead–zirconate–titanate and lead targets are studied as a function of ambient gas (argon or oxygen), gas pressure, and substrate temperature. When the substrate is kept in vacuum and at room temperature, a dip in the lead content attributable to the intrinsic resputtering of lead is observed at the position of the target surface normal. In the presence of an ambient gas, the dip disappears and the lead content increases at all angles. These results are attributed to a reduction of resputtering arising from scattering of the ablated species by ambient gas molecules. Under ambient oxygen and at high substrate temperature, the retention of lead content in the deposited films is largely due to the formation of lead oxide. © 1996 American Institute of Physics.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 5 (1994), S. 215-220 
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effects of tin doping on the deep-level photoluminescence (PL) spectra of (LEC) InP were studied. Specifically, the effect of rapid thermal annealing (RTA) on the deep emission bands labelled as band A (1.13 eV), band B (1.06 eV), band C (1.20 eV) and band D (0.97 eV) were investigated. Band A appeared in both undoped and doped samples, but it disappeared after RTA for all the samples. It is suggested that band A is due to the formation of a complex involving VIn with residual impurities. The disappearance of band A after RTA is concomitant with the appearance of bands B, C and D. The existence of band B is attributed to the complex formation of VP with residual impurities. Band C was observed after the annealing process both in undoped and lightly-tin-doped samples and is believed to be due to the formation of VP single point defects. Band D was only observed in heavily doped samples and it is believed to be the effect of InP antisite defects.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 9 (1990), S. 216-218 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 9
    ISSN: 1432-0630
    Keywords: PACS: 68.60; 81.15 ; 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 properties of Pulsed-Laser-Deposited Diamond-Like Carbon (PLD DLC) films are studied as functions of the power density Φ and the wavelength λ of the laser beam, and the incident angle ϑ of the beam relative to the normal of the target surface. All the films have a similar structure consisting of graphite particulates embedded in a continuous matrix, so the macroscopic performance of the films is determined by the overall contributions of the particulates and the matrix. The use of higher Φ, shorter λ, or larger ϑ leads to an enhancement of the diamond-like characteristics and a simultaneous increase of the particulate density. These two effects give opposite contributions to the electrical conductivity σR, leading to the following results. (i) σR drops with increasing Φ in the low Φ range (region I) due to the stronger diamond-like nature of the matrix, but increases sharply after Φ has exceeded a threshold Φmin as a result of the rapid increase in particulate density. (ii) In region I, the use of shorter λ or larger ϑ leads to a more diamond-like matrix, and this overwhelms the degradation effect caused by the slight increase in particulate density. The samples thus become more insulating. In the high Φ region (region II), however, the use of shorter λ or larger ϑ gives rise to higher particulate density, thereby increasing the electrical conductivity.
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  • 10
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The changes in the structure of reactive pulsed laser-deposited (RPLD) CNx films with nitrogen content from 3.6–22 at% have been investigated by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Fourier transform–infrared (FT–IR) absorption. The films were found to be amorphous, and to consist of a network of rings. The rings that were composed solely of carbon atoms gave rise to an XPS peak located between 284.3 and 284.8 eV (C1 component). The rings containing nitrogen led to another peak located between 285.5 and 286.4 eV (C2 component). When the nitrogen content increased, the relative intensity of the C1 component fell, while that of the C2 component rose, indicating that some carbon atoms in the rings were replaced by nitrogen atoms. C≡N bonds also contributed to the C2 component. The FT–IR data were consistent with this interpretation. No evidence for the existence of a β-C3N4 phase was found in RPLD CNx films.
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