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Author Tang, Dinghao ♦ Kim, Yeongho ♦ Faleev, Nikolai ♦ Honsberg, Christiana B. ♦ Smith, David J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ABUNDANCE ♦ ACTIVATION ENERGY ♦ ANTIMONY ♦ CARRIER LIFETIME ♦ DISLOCATIONS ♦ ELECTRON MICROSCOPY ♦ ELECTRONS ♦ GALLIUM ARSENIDES ♦ HOLES ♦ INDIUM ARSENIDES ♦ LUMINESCENCE ♦ MEV RANGE ♦ MOLECULAR BEAM EPITAXY ♦ PHOTOVOLTAIC EFFECT ♦ QUANTUM DOTS ♦ RED SHIFT ♦ RELAXATION ♦ SOLAR CELLS ♦ SUBSTRATES ♦ X-RAY DIFFRACTION
Abstract The structure-performance properties of single-layered and multi-layered InAs/GaAs{sub 1−x}Sb{sub x} quantum dot (QD) system, grown by molecular beam epitaxy on GaAs (001) substrates, have been investigated as a function of Sb concentration. Electron microscopy observations showed no significant crystalline defects for the single-layered InAs QDs (Sb 20%). X-ray diffraction analysis revealed that the increase of Sb concentration from 7.3% to 10.2% for the multi-layered QDs increased the strain relaxation from 0% to ∼23% and the dislocation density of GaAsSb layers went up to 3.6 × 10{sup 9 }cm{sup −2}. The peak energy of QD luminescence was red-shifted with increasing Sb concentration due to reduced strain inside QDs. Moreover, the carrier lifetime of the QDs was highly improved from 1.7 to 36.7 ns due to weak hole confinement as the Sb concentration was increased from 7.3% to 10.2%. These structures should be highly promising as the basis for photovoltaic solar-cell applications. Finally, the increased Sb concentration increased the thermal activation energy of electrons confined in the QDs from 163.7 to 206.8 meV, which was indicative of the improved thermal stability with Sb concentration.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-09-07
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 118
Issue Number 9


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