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Title: Resonant quantum efficiency enhancement of midwave infrared nBn photodetectors using one-dimensional plasmonic gratings

We demonstrate up to 39% resonant enhancement of the quantum efficiency (QE) of a low dark current nBn midwave infrared photodetector with a 0.5 μm InAsSb absorber layer. The enhancement was achieved by using a 1D plasmonic grating to couple incident light into plasmon modes propagating in the plane of the device. The plasmonic grating is composed of stripes of deposited amorphous germanium overlaid with gold. Devices with and without gratings were processed side-by-side for comparison of their QEs and dark currents. The peak external QE for a grating device was 29% compared to 22% for a mirror device when the illumination was polarized perpendicularly to the grating lines. Additional experiments determined the grating coupling efficiency by measuring the reflectance of analogous gratings deposited on bare GaSb substrates.
Authors:
; ; ; ; ; ; ; ; ; ;  [1] ;  [2]
  1. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)
  2. Sotera Defense Solutions, Inc., 7230 Lee Deforest Dr. Suite 100, Columbia, Maryland 21046 (United States)
Publication Date:
OSTI Identifier:
22483110
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 26; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CURRENTS; DEPOSITS; EQUIPMENT; GALLIUM ANTIMONIDES; GERMANIUM; GOLD; GRATINGS; LAYERS; MIRRORS; PHOTODETECTORS; QUANTUM EFFICIENCY; SUBSTRATES