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Title: Alloy inhomogeneity and carrier localization in AlGaN sections and AlGaN/AlN nanodisks in nanowires with 240–350 nm emission

We present structural and optical studies of AlGaN sections and AlGaN/AlN nanodisks (NDs) in nanowires grown by plasma-assisted molecular beam epitaxy. The Al-Ga intermixing at Al(Ga)N/GaN interfaces and the chemical inhomogeneity in AlGaN NDs evidenced by scanning transmission electron microscopy are attributed to the strain relaxation process. This interpretation is supported by the three-dimensional strain distribution calculated by minimizing the elastic energy in the structure. The alloy inhomogeneity increases with the Al content, leading to enhanced carrier localization signatures in the luminescence characteristics, i.e., red shift of the emission, s-shaped temperature dependence, and linewidth broadening. Despite these effects, the emission energy of AlGaN/AlN NDs can be tuned in the 240–350 nm range with internal quantum efficiencies around 30%.
Authors:
; ; ;  [1] ;  [2] ;  [1] ;  [2]
  1. Université Grenoble Alpes, 38000 Grenoble (France)
  2. (France)
Publication Date:
OSTI Identifier:
22395528
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM NITRIDES; GALLIUM NITRIDES; INTERFACES; LUMINESCENCE; MOLECULAR BEAM EPITAXY; NANOWIRES; PLASMA; QUANTUM EFFICIENCY; RED SHIFT; RELAXATION; STRAINS; TEMPERATURE DEPENDENCE; THREE-DIMENSIONAL LATTICES; TRANSMISSION ELECTRON MICROSCOPY