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Title: High internal quantum efficiency in AlGaN multiple quantum wells grown on bulk AlN substrates

The internal quantum efficiency (IQE) of Al{sub 0.55}Ga{sub 0.45}N/AlN and Al{sub 0.55}Ga{sub 0.45}N/Al{sub 0.85}Ga{sub 0.15}N UVC MQW structures was analyzed. The use of bulk AlN substrates enabled us to undoubtedly distinguish the effect of growth conditions, such as V/III ratio, on the optical quality of AlGaN based MQWs from the influence of dislocations. At a high V/III ratio, a record high IQE of ∼80% at a carrier density of 10{sup 18 }cm{sup −3} was achieved at ∼258 nm. The high IQE was correlated with the decrease of the non-radiative coefficient A and a reduction of midgap defect luminescence, all suggesting that, in addition to dislocations, point defects are another major factor that strongly influences optical quality of AlGaN MQW structures.
Authors:
; ; ;  [1] ; ;  [2]
  1. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
  2. HexaTech, Inc., 991 Aviation Pkwy., Suite 800, Morrisville, North Carolina 27560 (United States)
Publication Date:
OSTI Identifier:
22398850
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 14; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM NITRIDES; CARRIER DENSITY; DISLOCATIONS; GALLIUM NITRIDES; LUMINESCENCE; POINT DEFECTS; QUANTUM EFFICIENCY; QUANTUM WELLS; SUBSTRATES