摘要:

A thin (∼400 A˚) LPE In1−xGaxP1−zAsz’’trap’’ on thep‐type side of an InP junction [Eg(InP)−Eg(InGaPAs) ≡&Dgr;E∼245 meV], is filled by injection to a high enough density to make it possible to observe confined‐particle states and laser modes in a 70‐meV (≳600 A˚) range. The position of the modes is in good agreement with the transition energies expected for a finite potential well.

ISSN:0003-6951    

DOI:10.1063/1.89767

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Narrowband photovoltaic detectors were prepared using two PbySn1−ySe epitaxial layers of slightly different alloy compositions grown on BaF2substrates. Using Pb to form Schottky barrier detectors has yielded devices withD*&lgr;(10.6 &mgr;m) =7.0×1010cm Hz1/2 W−1and spectral half‐bandwidths of 6000 A˚. These devices are insensitive to variations in incident angle due to the large refractive indices of PbySn1−ySe.

ISSN:0003-6951    

DOI:10.1063/1.89768

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A deep (0.82 eV) impurity level has been observed via transient capacitance measurements in GaAs prepared under various gas‐phase stoichiometries. The density of these impurities increased with increasing AsH3/GaCl ratio in the vapor phase ranging from 2×1013cm−3for a 1/3 ratio to 9×1013cm−3for a 3/1 ratio. The minority‐carrier lifetime in these same samples decreased from 15 to 5 nsec with increasing AsH3/GaCl ratio. These deep levels, which serve as recombination centers for lifetime reduction, appear to originate from point defects introduced by deviations from stoichiometry toward the As‐rich side.

ISSN:0003-6951    

DOI:10.1063/1.89769

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Electron multipacting in a 2.8‐GHz TM010‐mode anodized niobium test cavity at 1.4 K has been studied experimentally. An electron multipactor simulation computer program, which we developed, successfully calculates the multipactor field levels and multipactor location observed experimentally and also provides additional details of the multipactor phenomena. With the multipactor simulation program, a sharp‐cornered TM010‐mode cavity has been designed in which multipacting is greatly reduced. A subsequent experiment on such a sharp‐cornered anodized niobium cavity has shown that electron multipacting is in fact eliminated for this cavity up through the highest field achieved. This work has shown that, with a simple modification in geometry, multipacting can probably be eliminated in the superconducting structure for the Stanford electron accelerator.

ISSN:0003-6951    

DOI:10.1063/1.89770

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The electronic contribution to stopping of 127 ion‐target combinations is calculated by the use of an expression for scaling from proton stopping powers. The scaling is found to be accurate, with a standard error of 4.5% relative to experimental measurements. Also, an evaluation is made of a recently proposed nuclear stopping formalism and evidence is found that it is more accurate than LSS nuclear stopping.

ISSN:0003-6951    

DOI:10.1063/1.89771

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Stoneley waves have long been assumed to exist between rock strata deep within the earth’s crust. We report the first direct measurements of Stoneley waves, in this case generated at 8 MHz and propagated along nickel‐Pyrex and other interfaces. The optically measured wavelengths agree with calculated values within 1%. The waves are not detected between unsuitable material pairs. Possible applications are suggested.

ISSN:0003-6951    

DOI:10.1063/1.89772

出版商:AIP    

年代:1977

数据来源: AIP