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Title: Evidence for a defect level above the conduction band edge of InAs/InAsSb type-II superlattices for applications in efficient infrared photodetectors

We report pressure-dependent photoluminescence (PL) experiments under hydrostatic pressures up to 2.16 GPa on a mid-wave infrared InAs/InAs{sub 0.86}Sb{sub 0.14} type-II superlattice (T2SL) structure at different pump laser excitation powers and sample temperatures. The pressure coefficient of the T2SL transition was found to be 93 ± 2 meV·GPa{sup −1}. The integrated PL intensity increases with pressure up to 1.9 GPa then quenches rapidly indicating a pressure induced level crossing with the conduction band states at ∼2 GPa. Analysis of the PL intensity as a function of excitation power at 0, 0.42, 1.87, and 2.16 GPa shows a clear change in the dominant photo-generated carrier recombination mechanism from radiative to defect related. From these data, evidence for a defect level situated at 0.18 ± 0.01 eV above the conduction band edge of InAs at ambient pressure is presented. This assumes a pressure-dependent energy shift of −11 meV·GPa{sup −1} for the valence band edge and that the defect level is insensitive to pressure, both of which are supported by an Arrhenius activation energy analysis.
Authors:
; ; ;  [1] ; ;  [2]
  1. Advanced Technology Institute and Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)
  2. Center for Photonics Innovation and School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States)
Publication Date:
OSTI Identifier:
22398952
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 17; 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; ACTIVATION ENERGY; CHARGE CARRIERS; EV RANGE; EXCITATION; INDIUM ANTIMONIDES; INDIUM ARSENIDES; PHOTODETECTORS; PHOTOLUMINESCENCE; PRESSURE COEFFICIENT; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; RECOMBINATION; SUPERLATTICES; VALENCE