An indirect method of studying band alignments in nBn photodetectors using off-axis electron holography
Abstract
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 × 1017/cm3 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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 21, 2015
- Source ID
- 10.1063/1.4931938
Entities
People
- David J Smith
- Martha R. Mccartney
- S. Liu
- Xiao-Meng Shen
- Yong-hang Zhang
- Zhao-yu He
- Zhi-yuan Lin
Organizations
- Air Force Office of Scientific Research
- Arizona State University
- Army Research Office