摘要:

Formation of vanadium silicides by the interactions of vanadium with bare and oxidized Si wafers has been studied by both x‐ray diffraction and He ion backscattering techniques. X‐ray diffraction was used to identify phases and ion backscattering to profile compositional changes. In the case of V on Si, the silicide VSi2, which is a silicon‐rich phase, was found to form at temperatures from 600 to 1000 °C. In the case of V on SiO2, reactions took place only at temperatures above 800 °C, and the reaction products were identified to be V3Si, V5SI3, and V2O5. Both V3Si and V5Si3are vandium‐rich phases, and the V3Si that we found was a continuous layer between the substrate and the other two phases, and became superconducting at about 15 °K.

ISSN:0003-6951    

DOI:10.1063/1.1654972

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Electromigration‐induced failure in NiCr thin‐film stripes is investigated. The composition of evaporated NiCr thin films is 77:23 Ni/Cr in weight %, according to a spectroscopic analysis. The mean time to failure (MTF) of NiCr thin‐film stripes can be qualitatively expressed by a relation similar to that held in the MTF of Al thin‐film stripes, i.e., MTF ∝J−nexp(&jgr;/kT). However, the values ofnand &jgr; of NiCr are 13 and 1.14 eV, respectively, whereas those of Al are 2 [inverted lazy s] 3 and 0.41 eV, respectively.

ISSN:0003-6951    

DOI:10.1063/1.1654973

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

We study theoretically and experimentally the collinear mixing of acoustic waves in lead molybdate. Owing to the large coupling constant of this crystal, we have obtained a very efficient acoustic mixer or modulator via the interaction of a 750‐MHz hypersonic signal wave and a 140‐MHz ultrasonic pump wave.

ISSN:0003-6951    

DOI:10.1063/1.1654974

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A theory of electromechanically induced acoustic phonon echoes is presented. The predicted echo pulse height and width are found to depend on the exciting pulse widths and frequencies, in agreement with experimental observations. Interesting new experiments with much larger predicted echo effects are suggested.

ISSN:0003-6951    

DOI:10.1063/1.1654975

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

An algebraic error is found in a recently published letter. Because of this error, coupled with an oversimplified assumption, an incorrect conclusion is obtained.

ISSN:0003-6951    

DOI:10.1063/1.1654976

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The cross sections for second harmonic generation of surface acoustic waves have been calculated from the rigorous theory of thermoelasticity. In this treatment, the nonlinear wave equation is satisfied by mechanical displacements which also maintain the boundary stress free at the harmonic frequency. Calculations for various cuts on &agr;‐quartz and sapphire are presented.

ISSN:0003-6951    

DOI:10.1063/1.1654977

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A new type of plasma instability is described in an electron‐beam ionized discharge. This instability occurs in gas mixtures in which the dissociative attachment rate increases strongly with electric field. It has been observed experimentally in He:H2O 740:20 and in He:CO21:1 and 9:1 mixtures. The values of the ionization source functionSand of the electric fieldEat which the wave instability occurs are predicted using a Fourier analysis of the linearized kinetic rate equations. This yields the condition for instability asS< (1/&agr;)[E&dgr;&bgr;/&dgr;E) − &bgr;]2, where &agr; is the electron‐ion recombination coefficient and &bgr; is the electron neutral attachment rate.

ISSN:0003-6951    

DOI:10.1063/1.1654978

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Optical data are presented relating the photoluminescence emission of GaAs : Ge epitaxial layers with hole concentrations in the range from 6 × 1016to 2.7 × 1019cm−3. These data are supplemented with electroluminescence results obtained using diodes where thepside of the junction consists of GaAs : Ge. Measurements reported include the peak position of the electroluminescence and photoluminescence peaks, half‐intensity bandwidths, and radiative efficiency at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.1654979

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A copper vapor laser utilizing copper chloride as a lasant in a heated discharge tube has been studied. The lasing action was observed only when two successive discharge current pulses at suitable time intervals were applied. The first pulse is considered to be a dissociation pulse to produce copper and chlorine atoms; the second to be a pumping pulse to produce population inversion. The maximum energy density measured to date was 17 &mgr;J/cm3.

ISSN:0003-6951    

DOI:10.1063/1.1654980

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Far‐infrared generation by optical mixing and by stimulated Raman scattering via spin‐flip transitions is treated using the general formalism of coherent excitation of polaritons. Practical numerical examples for InSb are given. The result for the case of optical mixing agrees well with the experimental result of Nguyen and Bridges. The calculation also suggests that the far‐infrared output from a spin‐flip Raman laser should be easily observable.

ISSN:0003-6951    

DOI:10.1063/1.1654981

出版商:AIP    

年代:1973

数据来源: AIP