摘要:

Tables ofK(&ggr;) andL(&ggr;) as defined by Willardsonet al.are given over the range in which simple (high and low field) approximations are not valid. The tables permit easy multi‐band calculation of the transverse magnetoresistance and isothermal Hall coefficient as a function of magnetic field in nondegenerate semiconductors in the lattice scattering range.

ISSN:0021-8979    

DOI:10.1063/1.1702601

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

It has been shown through means of transmission electron microscopy that precipitate particles decorate grown‐in dislocations in commercially available single crystal MgO. It has now been possible to show by means of electron diffraction that these precipitate particles are ZrO2and that they are formed even when the Zr concentration in the MgO is as low as 1 ppm.

ISSN:0021-8979    

DOI:10.1063/1.1702602

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The increase in the concentration of lattice defects during deformation of copper is shown to have a power law dependence on strain, i.e., &Dgr;&rgr;=c&Dgr;&egr;n, where &Dgr;&rgr; is the change in electrical resistivity at 78°K following an elongation strain increment &Dgr;&egr;, andcandnare constants. It is further shown that the initial internal condition of the metal affects the subsequent defect deformation in the metal. Finally it is shown that following room temperature anneal the production of defects is enhanced.

ISSN:0021-8979    

DOI:10.1063/1.1702603

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The ranges in solids of atoms having energies from 1 to 100 keV have been calculated using Monte Carlo techniques. The model assumes that the moving atom loses all of its energy through binary elastic collisions with the atoms of the solid. The potential of interaction, principally studied, is an exponentially screened Coulomb (Bohr) potential, and the scattering angles are calculated explicitly. It is found that neither the hard sphere approximation nor the inverser‐squared approximation to the Bohr potential is particularly good. To obtain correspondence with experimental results it is found that the Bohr screening length must be increased as the atomic number of the interacting atoms increases.

ISSN:0021-8979    

DOI:10.1063/1.1702604

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The piezoresistive properties ofn‐ andp‐type layers formed by the diffusion of impurities into silicon have been investigated. The values of the three piezoresistance coefficients and the temperature dependence of the large coefficients have been measured on layers having surface concentration values from 1018to 1021cm−3. The piezoresistance effect inp‐type diffused layers follows qualitatively the behavior expected in a degenerate semiconductor.n‐type layers having high surface concentration values show a change in the symmetry of the piezoresistance effect at room temperature and a decrease in the coefficient &pgr;11at lower temperatures. A discussion of the piezoresistance effect in diffused layers and its relation to the piezoresistance effect in uniformly doped material is also given.

ISSN:0021-8979    

DOI:10.1063/1.1702605

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

It has recently been found that particles of contamination reside on surfaces inside vacuum systems as a result of thermal decomposition of glass. These particles contain at least Na, K, and B as well as traces of Al and Si. They may well have been important in many clean surface experiments. Our investigation has shown that these particles have a strong influence in reducing the breakdown voltage in vacuum. Breakdown voltages for Al, Cu, and stainless steel electrodes with radii of curvature of 12.7, 25.4, 50.8, and 101.6 mm were determined under clean and contaminated conditions at 10−5Torr. It was found that under clean conditions the electrodes of smaller radii of curvature have higher breakdown voltages than the more nearly plane electrodes.

ISSN:0021-8979    

DOI:10.1063/1.1702606

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The stability of the shape of a spherical particle undergoing diffusion‐controlled growth into an initially uniformly supersaturated matrix is studied by supposing an expansion, into spherical harmonics, of an infinitesimal deviation of the particle from sphericity and then calculating the time dependence of the coefficients of the expansion. It is assumed that the pertinent concentration field obeys Laplace's equation, an assumption whose conditions of validity are discussed in detail and are often satisfied in practice. A dispersion law is found for the rate of change of the amplitude of the various harmonics. It is shown that the sphere is stable below and unstable above a certain radiusRc, which is just seven times the critical radius of nucleation theory; analogous conclusions are obtained for the solidification problem. The results for the sphere are used to discuss the stability of nonspherical growth forms.

ISSN:0021-8979    

DOI:10.1063/1.1702607

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The differential capacitance measurement for determining the height of a Schottky barrier at a metal—semiconductor contact is based upon a number of assumptions. In practice, one or more of these assumptions may not be valid. Some of these deviations from the ``ideal case'' are examined in order to determine the effects of each upon the interpretation and validity of measurements on such contacts. Specifically, the effects of each of the following are considered: series resistance, traps in the depletion layer, effective contact area variation with depletion layer width, an insulating interfacial layer between the metal and semiconductor, semiconductor surface charge variation with bias voltage, and the reserve layer at the edge of the barrier. Experimental data for gold plated contacts to conducting cadmium sulfide single crystals are given to illustrate some of the results.

ISSN:0021-8979    

DOI:10.1063/1.1702608

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Piezoelectric, dielectric, and pyroelectric measurements were made on hexagonal BeO crystals grown in molten lithium molybdate flux. The piezoelectric constantd33∼0.24×10−12C/N, &egr;33T/&egr;0∼7.6, and the average free pyroelectric constant in the range −196° to 25°C is −3.4×10−10C/cm2°C. The sound velocity perpendicular to the polar axis is 12 000 m/sec. Although no absolute identification of crystal planes was made, it was concluded from the sign of the piezoelectric constantd33that the oxygen side of the closely coupled Be—O layer is that of principal growth and etch. Polarity of the crystal structure is reflected in typical crystal growth habits and in characteristic etch patterns which are described.

ISSN:0021-8979    

DOI:10.1063/1.1702609

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The frictional properties of rigid and plasticized PVC have been measured as a function of temperature, speed of test, applied load, and plasticizer content. It was found that the data could be correlated by the simple equationF=F*[1−exp(−kf)], whereFis the frictional force,F* is a limiting frictional force dependent upon temperature and composition, andfis the applied normal force. The constantsF* andkcould be correlated with the tensile strength and the bulk modulus, respectively. A mechanism of polymer frictional behavior is proposed.

ISSN:0021-8979    

DOI:10.1063/1.1702610

出版商:AIP    

年代:1963

数据来源: AIP