摘要:

Effects of ultrasonic waves propagating at an angle &Vthgr; relative to the direction of a dc magnetic field in nondegenerate piezoelectric semiconductors such asn‐type InSb have been studied by using a quantum treatment which is valid at high frequencies and in strong magnetic fields. The interaction of conduction electrons with waves is via deformation‐potential and piezoelectric couplings. Results show that variation of the direction of the magnetic field with respect to the direction of propagation of ultrasonic waves will affect the ultrasonic absorption coefficient and change in sound velocity. Therefore the absorption coefficient and change in sound velocity depend strongly on the dc magnetic field, the sound frequency, the temperature, and the direction of the propagation of ultrasonic waves relative to that of the field.

ISSN:0021-8979    

DOI:10.1063/1.328163

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Glasses containing Al2O3, Ga2O3, and Bi2O3with Li2O have been prepared by twin roller quenching. These glasses are found to exhibit reasonably high ionic conductivities and low electronic conductivities for Li2O concentrations exceeding 50 mole %. The conductivity increases rapidly with increasing Li2O content but does not differ greatly from system to system despite the large difference in the ionic radii of the trivalent cations, Al3+, Ga3+, and Bi3+. A simple model for the behavior is discussed.

ISSN:0021-8979    

DOI:10.1063/1.328164

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Microwave resonances inn‐type InSb spheres placed in a magnetic field are studied experimentally and analyzed in light of the recently developed theory of Ford and Werner for the interaction of electromagnetic waves with a gyrotropic sphere. The Ford‐Werner theory is a generalization of the Mie theory to the case of gyrotropic media. The present study constitutes an experimental check on the Ford‐Werner theory, demonstrating that the theory is capable of fitting microwave resonance spectra remarkably well. Magnetic and electric dimensional resonances and plasma‐shifted cyclotron resonance of gyrotropic semiconductor spheres are examined for their usefulness as accurate diagnostic measures of various material parameters, such as carrier concentration, the static dielectric constant, and carrier mobility. Special attention is given to establishing the limits of the accuracy of this method. For example, the static dielectric constant of the InSb lattice is found to be 16.8±0.2 from this set of measurements. Good theoretical fits are obtained for the resonance positions and shapes, but not for all of the resonance amplitudes. The discrepancy is attributed to an insufficiently accurate representation of the carrier system resulting from the use of the Drude free‐electron model in the present analysis.

ISSN:0021-8979    

DOI:10.1063/1.328165

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The Hall coefficient and resistivity of Hg1−xCdxTe epitaxial layers with 0.195<x<0.351, have been measured between 4 and 300 K. At 77 K the results forx=0.30 show that as‐grown epitaxial layers areptype, with a carrier concentration and mobility on the order of 1.2×1016cm−3and 400 cm2/V s, respectively. The acceptor ionization energy determined by the Hall measurements is found to change with the energy gap of Hg1−xCdxTe . The electrical parameters and compositional uniformity (&Dgr;x=±0.001) of the epilayer forx=0.30 indicate that the material is comparable to the best reported bulk Hg1−xCdxTe single crystal.

ISSN:0021-8979    

DOI:10.1063/1.328166

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Variations of the electronic work function of carburized rhenium foils containing approximately 5 at.% carbon have been observed using the contact potential difference technique. Surface work function was observed to vary between 5.25 and 4.1 eV, with the work function of pure rhenium taken as 5.0 eV. Decrease in work function has been ascribed to the formation of graphitic layers on the surface at temperatures below the temperature of saturated solubility. The high work function surface was observed with all carbon in solution and has been ascribed to the presence of amorphous carbon near the surface.

ISSN:0021-8979    

DOI:10.1063/1.328167

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Measurements of the energy distribution of electrons emitted in vacuum by very shallow siliconp‐njunctions are described. It has been found that diodes with the junction perpendicular to the surface show a relatively narrow peak and a broad band, while diodes with the junction parallel to the surface only give a narrow peak (half‐width 0.50 eV). The broad band is ascribed to electrons emitted from the depletion layer of the junction, and the narrow peak is attributed to electrons emitted from the neutralnlayer.

ISSN:0021-8979    

DOI:10.1063/1.328114

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The interfacial layer theory considering the surface fixed charge and the voltage drop across the interfacial layer is developed for the Schottky barrier diodes fabricated on then‐type semiconductor substrate. It is shown that the positive surface fixed charge will reduce the barrier height and then increases the reverse current; the voltage drop across the interfacial layer will increase the ideality factor of the forward biasedI‐Vcharacteristic and the voltage dependence of the reverse‐biasedI‐Vcharacteristic, aside from the effects of the image force lowering; the fluctuations of the experimental data deduced from the fabricated Schottky barrier diodes with different fabricating conditions are mainly due to the variations of the interfacial‐layer properties such as the interfacial‐layer thickness, the interface states, the surface fixed charges.

ISSN:0021-8979    

DOI:10.1063/1.328115

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Numerical solutions of the (field and diffusion) transport equations yield energy and concentration contours for thick M1‐I‐M2(metal‐insulator‐metal) barriers, and their appropriate current‐voltage relationships, with and without traps. Traps must ordinarily be expected in such films, and it is shown that they result in a curvature of the barrier profile, which exercises a controlling influence overI‐Vcharacteristics in the forward direction.

ISSN:0021-8979    

DOI:10.1063/1.328116

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Electrical properties of Se‐ and Zn‐doped polycrystalline GaAs deposited by metalorganic chemical vapor deposition on substrates of polycrystalline alumina and glass were investigated. Hall‐effect and resistivity measurements were made over a wide range of temperature (77–420 K). The electrical activation energies were found by measuring the variation of resistivity and carrier mobility of the polycrystalline GaAs films with sample temperature. The resistivity and mobility were found to be temperature activated over a wide temperature range as exp(Eb/kT) and exp(−Eb/kT), respectively, with the same activation energy applying to both properties. The results have been interpreted in terms of a modified grain boundary trapping model.

ISSN:0021-8979    

DOI:10.1063/1.328117

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

In a Josephson junction interferometer, the current flow between the junctions is not uniform along the stripe line. The current is crowded around the junctions and becomes uniform along the strip line only when it is far away from the junction area. The inductance of such a structure with nonuniform current flow is analyzed. Several analytical formulas are derived to calculate the loop inductance of a Josephson junction interferometer.

ISSN:0021-8979    

DOI:10.1063/1.328118

出版商:AIP    

年代:1980

数据来源: AIP