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Title: Al{sub x}Ga{sub 1-x}N-based back-illuminated solar-blind photodetectors with external quantum efficiency of 89%

We report on high performance Al{sub x}Ga{sub 1−x}N-based solar-blind ultraviolet photodetector (PD) array grown on sapphire substrate. First, high quality, crack-free AlN template layer is grown via metalorganic chemical vapor deposition. Then, we systematically optimized the device design and material doping through the growth and processing of multiple devices. After optimization, uniform and solar-blind operation is observed throughout the array; at the peak detection wavelength of 275 nm, 729 μm{sup 2} area PD showed unbiased peak external quantum efficiency and responsivity of ∼80% and ∼176 mA/W, respectively, increasing to 89% under 5 V of reverse bias. Taking the reflection loses into consideration, the internal quantum efficiency of these optimized PD can be estimated to be as high as ∼98%. The visible rejection ratio measured to be more than six orders of magnitude. Electrical measurements yielded a low-dark current density: <2 × 10{sup −9} A/cm{sup 2}, at 10 V of reverse bias.
Authors:
; ; ; ;  [1]
  1. Department of Electrical and Computer Engineering, Center for Quantum Devices, Northwestern University, Evanston, Illinois 60208 (United States)
Publication Date:
OSTI Identifier:
22254136
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 19; Other Information: (c) 2013 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; ALUMINIUM NITRIDES; CHEMICAL VAPOR DEPOSITION; CURRENT DENSITY; DESIGN; EQUIPMENT; PHOTODETECTORS; QUANTUM EFFICIENCY; SAPPHIRE; ULTRAVIOLET RADIATION