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Title: Three-dimensional spectrum mapping of bright emission centers: Investigating the brightness-limiting process in Eu-doped GaN red light emitting diodes

A pulse-driven emission-spectroscopy mapping technique is used to investigate the bright emission centers in Eu-doped GaN (GaN:Eu) red light emitting diodes (LED). The LEDs are operated in pulse-driven mode, and the emission spectra are acquired for a range of pulse frequencies. This ensemble of emission spectral data yields a three-dimensional mapping that allows the origin of emission lines to be identified by visual inspection. The identification was achieved even for a weak {sup 5}D{sub 0} → {sup 7}F{sub 3} transition in conventional photoluminescence measurements. A peculiar split is observed in the {sup 5}D{sub 0} → {sup 7}F{sub 3} transition for the bright emission center referred to as OMVPE 8. Despite the unique transition at this emission center, the emission efficiencies for the {sup 5}D{sub 0} → {sup 7}F{sub 3} and {sup 5}D{sub 0} → {sup 7}F{sub 2} transitions were identical. This finding indicates that the excitation of the emission centers, rather than the radiative transitions, is the limiting process that determines the GaN:Eu red LED brightness.
Authors:
 [1] ; ;  [2]
  1. National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 (Japan)
  2. Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan)
Publication Date:
OSTI Identifier:
22489155
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BRIGHTNESS; DOPED MATERIALS; EFFICIENCY; EMISSION SPECTRA; EMISSION SPECTROSCOPY; EXCITATION; GALLIUM NITRIDES; LIGHT EMITTING DIODES; MAPPING; PHOTOLUMINESCENCE; PULSES; THREE-DIMENSIONAL CALCULATIONS; THREE-DIMENSIONAL LATTICES