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Title: Emission mechanisms in Al-rich AlGaN/AlN quantum wells assessed by excitation power dependent photoluminescence spectroscopy

The optical properties of Al-rich AlGaN/AlN quantum wells are assessed by excitation-power-dependent time-integrated (TI) and time-resolved (TR) photoluminescence (PL) measurements. Two excitation sources, an optical parametric oscillator and the 4th harmonics of a Ti:sapphire laser, realize a wide range of excited carrier densities between 10{sup 12} and 10{sup 21 }cm{sup −3}. The emission mechanisms change from an exciton to an electron-hole plasma as the excitation power increases. Accordingly, the PL decay time is drastically reduced, and the integrated PL intensities increase in the following order: linearly, super-linearly, linearly again, and sub-linearly. The observed results are well accounted for by rate equations that consider the saturation effect of non-radiative recombination processes. Using both TIPL and TRPL measurements allows the density of non-radiative recombination centers, the internal quantum efficiency, and the radiative recombination coefficient to be reliably extracted.
Authors:
; ; ; ;  [1]
  1. Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan)
Publication Date:
OSTI Identifier:
22413145
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 7; 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; ALUMINIUM NITRIDES; CARRIER DENSITY; ELECTRONS; EMISSION SPECTROSCOPY; EXCITATION; EXCITONS; GALLIUM NITRIDES; HOLES; OPTICAL PROPERTIES; PARAMETRIC OSCILLATORS; PHOTOLUMINESCENCE; QUANTUM EFFICIENCY; QUANTUM WELLS; REACTION KINETICS; RECOMBINATION; SAPPHIRE; SOLID-STATE PLASMA; TIME RESOLUTION