摘要:

Hall‐effect measurements have been made on Te‐doped GaAs crystals diffused with known amounts of64Cu sufficient to convert the crystals top‐type. Energy levels are found above the valence band at 0.123±0.005 eV, 0.145±0.005 eV, 0.166±0.005 eV, 0.19±0.005 eV, and 0.43±0.01 eV. An analysis of the Hall data has been made by means of computer programs. The results may be summarized as follows: (1) Ga vacancies produced during the Cu diffusion associate with and neutralize Te as a compensating center. (2) The ionization energy of the TeCuGapair is 0.19 eV rather than 0.166 eV as suggested previously.

ISSN:0021-8979    

DOI:10.1063/1.1710016

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The electrical characteristics of diodes made from degeneraten‐type Ge with either Au or In as the metallic element are reported. The results support a previously published calculation [Phys. Rev. 150, 466 (1966)]. It is significant that the observation can be interpreted quantitatively. Data are presented in terms of the dependence of incremental resistancedv/dior conductancedi/dvon applied voltage. Maxima in the incremental resistance predicted to occur at an applied voltage which corresponds to the Fermi degeneracy of then‐type Ge are observed. Data for several values of impurity, density, and temperature are shown to correspond quantitatively with the prediction. However, evidence suggests the importance of band tailing, a feature not included in the calculation. Observation of several additional effects is also reported. Pronounced structure near zero bias appears when the metallic element is in the superconducting state. This is well described by the BCS theory. The threshold for tunneling into the conduction‐band minimum &Ggr;2′was also observed. From this the separation in energy with respect to theL‐band minima is determined to be &Ggr;2′−L=0.154±0.003 eV. Anomalous structure at zero bias similar to that observed by others inp‐njunctions and metal‐oxide‐metal structures is reported but not interpreted.

ISSN:0021-8979    

DOI:10.1063/1.1710017

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The thermal diffusivity and specific heat of Armco iron are reported in the temperature range of 25° to 1000°C. Electrical‐resistivity values are reported from −272° to 1000°C. The thermal‐diffusivity values as measured by several different methods on the same material are compared. The thermal conductivity is calculated from the thermal diffusivity and specific heat and compared with values reported from direct measurements by other investigators. These measurements were carried out as a contribution to a cooperative program for the characterization of Armco iron as a high‐temperature thermal‐conductivity standard. Armco iron appears to be a satisfactory thermal‐conductivity standard, with an error of 2% or less, from 25° to 700°C; above 700°C the thermal history of the iron sample becomes important and iron is less satisfactory as a standard. Reproducible values above 700°C may still be obtained, but only if the sample has had adequate heat treatment.

ISSN:0021-8979    

DOI:10.1063/1.1710018

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A study has been made of hillock‐like features which sometimes occur on {1, 0, 0} surfaces of epitaxial gallium arsenide. X‐ray diffraction topography reveals that the hillocks contain cores of twin which originate at, or near, the epitaxial interface. During growth of the layer the twins can become buried, leaving a surface which is matrix‐oriented.

ISSN:0021-8979    

DOI:10.1063/1.1710019

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

We report here measurements which indicate that at 0.278 keV the extrapolated aluminum mass absorption coefficient (24 500 cm2/g) is too small, and that a better value lies in the range 36 000–43 000 cm2/g. This result is consistent with recently reported measurements at higher energies, which indicate that early values of ultra‐soft x‐ray absorption coefficients were too low.

ISSN:0021-8979    

DOI:10.1063/1.1710020

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The differential equations describing diffusion‐controlled growth or dissolution of an isolated sphere in an infinite body of liquid have been solved numerically assuming constant interface concentration, constant diffusivity, and constant partial specific volume. The results for dissolving spheres are presented in a way which allows change of size with time to be interpolated for wide ranges of values of the two characteristic parameters. The results for growing spheres are compared with the analytical results for growth from zero initial size.

ISSN:0021-8979    

DOI:10.1063/1.1710021

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Films of Cu1.8S have been made by flash evaporation. They have a resistivity of 6.2×10−4&OHgr;·cm and an absorption coefficient to 1.5 eV radiation of 1.13×103cm−1. The corresponding quantities for Cu1.8Se are: 1.6×10−4&OHgr;·cm, and 1.18×103cm−1. The resistivity of Cu1.8Te films increases with time.It is found that if during flash evaporation the ratio of partial pressures of Cu and Se at the substrate fluctuates then the film does not have the composition of the charge.Cu1.8S has potential applications for producing transparent conducting coatings on substrateswhich cannot be heated above room temperature.

ISSN:0021-8979    

DOI:10.1063/1.1710022

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The lattice distortions in single‐crystal Si substrates due to stressed surface films were calculated by linear elastic theory. It is shown that the strains are localized directly underneath discontinuities in the films, and these regions are responsible for the enhanced diffracted intensity experimentally observed in x‐ray topographs of the substrate. A simplified theory is presented which is used to semiquantitatively describe the relationship between film stress and thickness, and enhanced diffracted intensity.

ISSN:0021-8979    

DOI:10.1063/1.1710023

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

As‐cast and controlled‐solidification structures have been produced in the Fe‐FeS eutectic. The latter structure consists of an aligned parallel array of Fe rods approximately 2 &mgr; in diameter embedded in and separated by a matrix of FeS. These rods grow with an [001] fiber texture such that the [001] direction coincides with the long direction of the Fe particles. Magnetization and torque results reveal distinct differences between the two structures. The magnetic properties that were determined for the eutectic alloy are interpreted with regard to the multidomain structure of the Fe particles and the relative contributions of the shape anisotropy and crystal anisotropy present in the Fe phase of the solidification structures.

ISSN:0021-8979    

DOI:10.1063/1.1710024

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The Gru¨neisen parameter has been defined as the pressure response in a material to a change in internal energy with the strains held constant. The Gru¨neisen parameter does not account for the oriented response of anisotropic materials; the Gru¨neisen tensor is developed to account for this response. The Gru¨neisen tensor is stated explicitly for several crystal classes. Alpha‐quartz is considered as an example of an anisotropic material, and specific values for its Gru¨neisen tensor are presented.

ISSN:0021-8979    

DOI:10.1063/1.1710025

出版商:AIP    

年代:1967

数据来源: AIP