摘要:

The upper critical fieldHc2(4.2 K) of superconducting Nb3Ge films prepared by sputtering and chemical vapor deposition (CVD) has been measured in a pulsed field. TheHc2of these films is generally related to their superconducting critical temperatureTc. Sputtered films exhibit a linear increase ofHc2from 25.4 to 33.3 T for aTcrange 18.6–21.3 K. Although the data of CVD‐prepared films are scattered due to nonuniformity in the films, a similar dependence ofHc2onTchas been found.

ISSN:0021-8979    

DOI:10.1063/1.336577

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The measurement of thermally grown silicon dioxide films on selected metal silicides (CoSi2, CrSi2, Ir3Si5, NiSi2, Ru2Si3, and WSi2) via ellipsometry has been investigated. The oxide‐thickness calculation requires a knowledge of the complex refractive index of the metal‐silicide substrate which can be measured independently by ellipsometry on bare silicide substrates. In order to check the measured refractive indices for the silicide substrates, the thicknesses of thermally grown SiO2films were compared from ellipsometry which used the measured refractive indices, Rutherford backscattering, and step‐height thickness measurements. It is shown that, despite considerable complexities introduced by various surface treatments, procedures have been found so that effective refractive indices for the silicide substrates can be obtained, which in some instances require removal of the oxide and measurement of the complex refractive index of the silicide after oxidation.

ISSN:0021-8979    

DOI:10.1063/1.336578

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We present a method for analyzing current‐voltage relationships to obtain information on the dominant conduction mechanisms. The method is based on the analysis of the derivative of the logarithmic conductivity with respect to inverse applied electrical field. To illustrate the method we apply it to the study of Co‐Al2O3and Au‐Al2O3composite films. The former material displays space‐charge‐limited conduction, which is due to a high density of trap states in the oxide matrix. On the other hand, Au‐Al2O3shows evidence of percolation and tunneling between metal particles.

ISSN:0021-8979    

DOI:10.1063/1.336579

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

In the magnetic field applied liquid‐encapsulated Czochralski (MLEC) GaAs crystals, midgap level EL2 concentrations have been found to be strongly affected by the melt composition and crystal versus crucible rotational conditions. Although the EL2 concentrations only varied from 1 to 4×1016cm−3in the conventional LEC GaAs crystals, they ranged from far below 1×1015cm−3in Ga‐rich melt to 1×1017cm−3in As‐rich melt for the MLEC GaAs crystals.

ISSN:0021-8979    

DOI:10.1063/1.336580

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The refractive indices of In0.49Ga0.51P, In0.49Al0.51P, and In0.49Ga0.29Al0.22P, lattice matched to GaAs grown by molecular‐beam epitaxy, are determined from double‐beam reflectance measurements for photon energies ranging from 0.6 to 1.3 eV. Variation of the In0.49Ga0.51−xAlxP, refractive index with Al compositionxand photon energy is calculated according to the single‐effective‐oscillator model. These analytical results are then compared with experimental data.

ISSN:0021-8979    

DOI:10.1063/1.336581

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The extrapolated rangeRexand the projected rangeRprof electrons in metal absorbers have been calculated using the Wilson expression for mean range of high‐energy electrons. The results are in good agreement with experimental values reported by Tabata, Ito, and Okabe [J. Appl. Phys.42, 3361 (1971)]. Schematic comparison of the calculated values with experimental data is made.

ISSN:0021-8979    

DOI:10.1063/1.336582

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

NdFe(B) thin films are deposited onto glass substrates by means of a tungsten crucible. The as‐deposited films are studied by the Lorentz microscopy method in order to observe the different magnetic domains. STEM analysis (EELS method) permits us to obtain the characteristic absorption edges of Fe and Nd (but not of boron). The crystallization behavior, inside the electron microscope, by means of the electron beam, allows us to observe the formation of the &agr;‐Fe,A‐Nd2O3, and NdFeO3phases. The different stages of appearances of these structures are discussed.

ISSN:0021-8979    

DOI:10.1063/1.336583

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A theory of alloy scattering of two‐dimensional electron gas in quaternary III‐V semiconductors is developed by assuming spherically symmetric square scattering potential randomly distributed in the crystal. The theory predicts a temperature‐independent mobility. Electron mobilities have been calculated for two‐dimensional electrons in Ga1−xInxP1−yAsyand Ga1−xInxP1−ySby, with scattering potentials expressed in terms of the differences in the band gaps, the electron affinities, and the electronegativities of the constituent materials.

ISSN:0021-8979    

DOI:10.1063/1.336584

出版商:AIP    

年代:1986

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.337050

出版商:AIP    

年代:1986

数据来源: AIP