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Title: An indirect method of studying band alignments in nBn photodetectors using off-axis electron holography

Mid-wave and long-wave infrared nBn photodetectors with absorbers consisting of InAs/InAsSb superlattices and barriers consisting of InAs/AlGaSb(As) superlattices were grown using molecular beam epitaxy. High-resolution X-ray diffraction showing significant differences in Ga composition in the barrier layer, and different dark current behavior at 77 K, suggested the possibility of different types of band alignments between the barrier layer and the absorber for the mid- and long-wave infrared samples. Examination of the barrier layers using off-axis electron holography showed the presence of positive charge with an estimated density of 1.8 × 10{sup 17}/cm{sup 3} in the mid-wave sample as a result of a type-II band alignment, whereas negligible charge was detected in the long-wave sample, consistent with a type-I band alignment.
Authors:
 [1] ;  [2] ; ; ; ;  [3] ;  [2] ; ;  [3] ;  [2]
  1. School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States)
  2. (United States)
  3. Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287 (United States)
Publication Date:
OSTI Identifier:
22482125
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DENSITY; DEPLETION LAYER; HOLOGRAPHY; INDIUM ARSENIDES; MOLECULAR BEAM EPITAXY; PHOTODETECTORS; RESOLUTION; SUPERLATTICES; X-RAY DIFFRACTION