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

Journal Article · Mon Sep 21 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4931938· OSTI ID:22482125

Shen, Xiao-Meng ^[1]; He, Zhao-Yu; Liu, Shi; Lin, Zhi-Yuan; Zhang, Yong-Hang ^[2]; Smith, David J.; McCartney, Martha R. ^[2]

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1. School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States)
2. Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287 (United States)

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.

• OSTI ID: 22482125
• Journal Information: Applied Physics Letters, Vol. 107, Issue 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DENSITY
DEPLETION LAYER
HOLOGRAPHY
INDIUM ARSENIDES
MOLECULAR BEAM EPITAXY
PHOTODETECTORS
RESOLUTION
SUPERLATTICES
X-RAY DIFFRACTION