摘要:

The refractive index as a function of optical wavelengths for ZnSe, a semiconductor, has been measured outside and within its broad absorption band. The data are presented in a table and in a dispersion curve.

ISSN:0021-8979    

DOI:10.1063/1.1713136

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

Single‐crystal GaP has been grown at rates up to 13 mils (330 &mgr;) per hour onto a GaAs substrate by using a close‐spaced vapor transport technique. The as‐grown layers are invariablyntype. Thin layers (3–6 mils, or 75 to 150 &mgr;) grown at slow rates are essentially strain‐free, while thicker layers grown more rapidly exhibit considerable strain. Hall measurements were made and show that the dominant donor has an activation energy of 0.089 eV. Mobilities as high as 120 cm2/V‐sec and carrier concentrations as low as 4×1015/cm3have been measured. The Hall data imply an effective mass of 0.25m. The decay of pulse‐injected excess carriers indicate a lifetime of about 1 &mgr;sec and the presence of several deep traps. Photovoltaic measurements were made and are discussed.

ISSN:0021-8979    

DOI:10.1063/1.1713137

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

Expressions for the electrical conductivity &sgr; and the isothermal Hall coefficientAHare transcendental equations in terms of film thickness and are solved graphically for film thickness. Measurements on vacuum‐deposited gold films in the thickness range 150–500 Å are compared with thickness measurements based upon the multiple beam interferometer methods of Tolansky and upon thickness calculations from microgram weighings. The deviations in measured film thickness are relatively constant, having a value of 30 Å for films greater than 300 Å. This constant deviation can be eliminated if the electron mean free path in bulk material is 370 Å in place of the value given in the literature (410 Å).

ISSN:0021-8979    

DOI:10.1063/1.1713138

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

Boron‐doped germanium having very low levels of compensation is shown to be useful for detection of far infrared radiation in the 50–125 &mgr; range. The results of measurements of time constant, dc characteristics, photoresponse, and spectral response of several Ge(B) detectors is presented and discussed. Detectors having a peak detectivity of 2.1×1011cm‐cps½‐W−1at 108 &mgr; and a low dynamic impedance have been achieved. The cross section for the capture of a free hole by an ionized boron impurity in germanium at 4.2°K, about 4×10–11cm2, is significantly larger than the corresponding cross section forn‐type impurities in germanium.

ISSN:0021-8979    

DOI:10.1063/1.1713139

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The theoretical problem of one‐carrier, space‐charge‐limited current flow is beyond the reach of analytical solutions when trapping and diffusion are included in the analysis. Nonetheless, the problem for the semiinfinite solid very generally lends itself to rather simple numerical solution on a digital computer. An interesting feature of the machine solution is that it is based on a universal geometric property of the one dimensional, planar current flow. Detailed solutions are obtained for several special cases of the trap‐filled insulator problem which plays a fundamental role in the space‐charge‐limited current measurement of trap densities in insulators. A comparison of these exact solutions with the analytical solutions neglecting diffusion indicates that an error of a factor of two might be made in a trap density determination for the typical case which is completely studied. A brief discussion of the problem of extending the technique to the finite solid with an anode constraint is given. Also a few computer results for the Ohm's law problem are given.

ISSN:0021-8979    

DOI:10.1063/1.1713140

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The defect which appears inp‐type silicon quenched from 870° to 1070°K is characterized by an ionization energy about 0.4 eV from the valence band, by an activation energy for motion about 0.3 eV, and by a diffusion constant of 1.2×10−7cm2/sec at room temperature. The principal feature of the defect during room temperature annealing is that it fits into dimension‐dependent kinetics. This indicates that the process of elimination of the defect occurs at the surfaces of the samples and that in thicker samples only a fraction of the defects succeed in reaching the surfaces. The high diffusion constant makes it plausible that the defect is an interstitial silicon. Mayburg in 1956 concluded from a series of experiments that interstitials exist in large densities (∼1016cm−3) in silicon crystals as grown; he also considered their motion to the surfaces. We believe that the present experiments point to activation of interstitials during the heating process. They may have existed in an electrically inactive form in the crystals as grown, i.e., near some imperfection. Their random diffusion brings them to the surfaces where again they lose their donor properties.

ISSN:0021-8979    

DOI:10.1063/1.1713141

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The interaction between particles and an advancing solid‐liquid interface has been investigated both experimentally and theoretically. For each particular type of particle, a ``critical velocity'' was observed, below which the particles are rejected by the interface, and above which they are trapped in the solid. The dependence of the critical velocity on various properties of matrix and particle was investigated. A theory has been developed, based on the assumption that a very short‐range repulsion exists between the particle and the solid. This repulsion occurs when the particle‐solid interfacial free energy is greater than the sum of the particle‐liquid and liquid‐solid interfacial free energies. The particle is pushed along ahead of the advancing interface and becomes incorporated into the solid if liquid cannot diffuse sufficiently rapidly to the growing solid behind the particle. Reasonable agreement was obtained between the calculated and experimentally observed critical velocities.

ISSN:0021-8979    

DOI:10.1063/1.1713142

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The preparation from vapor and the structure of filamentary crystals of silicon have been studied in detail. It was found by chemical etching, by examination for a twist associated with a screw dislocation, and by observations in the electron microscope, that both ribbons and needles of small dimensions are free of dislocations and imperfections. Certain impurities such as gold, nickel, or platinum, however, are essential for the growth of filamentary crystals.The growth of micron size and larger whisker crystals from the vapor takes place in two stages. The first is a rapid extension in length of a leader‐like crystal of small cross section; the second, a slow thickening of the leader through deposition on lateral faces. Initial growth is associated with impurities and does not require an axial screw dislocation. Subsequent growth may be explained by classical nucleation at a step and lateral translation of the step.

ISSN:0021-8979    

DOI:10.1063/1.1713143

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The effect of elastic interaction on the distribution of vacancies around Guinier‐Preston zones of the first kind (GP [1]) is investigated. The elastic interaction between a small disk‐shaped GP [1] zone and an initially uniform distribution of quenched‐in vacancies causes the rapid formation of a vacancy atmosphere surrounding the zone. This atmosphere has an appreciable effect on the early rate of growth of the zone.

ISSN:0021-8979    

DOI:10.1063/1.1713144

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

Critical regions at the level of significance &agr;=1%, 5%, 10%, and 20% have been calculated for testing whether or not a sample ofNsingle, cubic crystals is randomly oriented. The stereographic triangle has been divided into five cells in two different ways, one with respect to important crystallographic directions in fcc crystals and one with respect to those in bcc crystals. Representative tables forN=10 for fcc and for bcc crystals and forN=20 bcc crystals are presented.

ISSN:0021-8979    

DOI:10.1063/1.1713145

出版商:AIP    

年代:1964

数据来源: AIP