摘要:

We formulate a kinetic description of the vertical exchange reaction in which Ga replaces In during migration enhanced epitaxy of GaAs on InAs. Considering the Ga deposition rateRto be finite rather than infinite, as was done previously, leads to a reinterpretation of experimental results. The kinetic coefficientkas found by comparison with the In concentration profile determined by secondary ion mass spectroscopy is found to be 25&percent; greater at 500 °C, cycle time of 5 s andR=12 s−1than that found earlier. The probability of an In atom being replaced by a newly deposited Ga atom, which depends on the details of the Ga deposition schedule, is determined and found to be identical, 98&percent;, for these conditions to that found earlier. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366528

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Intersubband transitions in GaAs/GaAlAs multiquantum wells (QW) under hydrostatic pressure have been investigated with photomodulated transmission spectroscopy and free-standing QW samples. In addition to the direct transitions associated with the &Ggr; critical points, severalL-related transitions between theLconduction band and the &Ggr; valence band of the GaAlAs barriers and between theLconduction subbands and the &Ggr; valence subbands inside the GaAs quantum wells are observed. The distinctL-related spectral features are a clear indication that photomodulated transmission is particularly useful for enhancement of the weak phonon-assisted indirect transitions. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366529

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Data are presented on the dependence of Al content on the formation of InAlGaAs quantum dots grown by strained-layer molecular beam epitaxy. Atomic force microscopy and reflection high-energy electron diffraction patterns show that the addition of Al both slows the formation of the quantum dots in the brief time following layer deposition, and results in smaller dots of higher density. The effects might be qualitatively explained by reduced surface migration of the column III atoms due to the stronger Al bond strength. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366530

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The combined effects of suppressing Auger recombination in strained layer superlattices (SL), photon recycling, and the suppression of both Auger and radiative recombination with carrier depletion are calculated quantitatively for a 11 &mgr;m 35.9 Å InAs/15.7 ÅIn0.225Ga0.775Sband a 3.5 &mgr;m 16.7 Å InAs/35 ÅIn0.25Ga0.75SbSL operating at temperatures between 200 and 300 K. The results are compared to their HgCdTe counterparts. The SL performance is better in all cases. However, the carrier concentrations required for background limited performance (300 K, 2&pgr; field of view), ranging between about1×1013and4×1013 cm−3at 300 K in both SLs, are seen to be impractically low. The carrier concentration in a 11 &mgr;m photon detector yielding equivalent performance to a 300 K thermal detector is about1014 cm−3.Large performance enhancement using carrier depletion therefore appears impractical even in optimized SLs. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366531

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

It is pointed out that there are some errors existing in a recent investigation in this journal [M. Yamanishi, J. Appl. Phys.80, 5494 (1996)]. The correct results are given so that one can better understand the performance of real thermoelectric cooler systems. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366517

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The relevant results [M. Yamanashi (J. Appl. Phys.80, 5494 (1996)] are correct because the numerical simulations were performed by using dimensionless thermoelectronic cooling (TEC) system equations. These equations can be used to optimize a TEC in a TEC system whenp- andn-type thermoelements have different geometrical factors(lp/Sp≠ln/Sn).Usefulness of exergetic efficiency and the definition of the maximum dimensionless entropy flow are also explained. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366518

出版商:AIP    

年代:1997

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.366538

出版商:AIP    

年代:1997

数据来源: AIP