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Title: Investigation of single-layer/multilayer self-assembled InAs quantum dots on GaAs{sub 1-x}Sb{sub x}/GaAs composite substrates

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.
Authors:
 [1] ; ; ;  [2] ;  [3]
  1. School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States)
  2. School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States)
  3. Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)
Publication Date:
OSTI Identifier:
22494827
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 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