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Title: Structural and optical characterization of Mg-doped GaAs nanowires grown on GaAs and Si substrates

We report an investigation on the morphological, structural, and optical properties of large size wurtzite GaAs nanowires, low doped with Mg, grown on GaAs(111)B and Si(111) substrates. A higher density of vertical nanowires was observed when grown upon GaAs(111)B. Very thin zinc-blende segments are observed along the axis of the nanowires with a slightly higher linear density being found on the nanowires grown on Si(111). Low temperature cathodoluminescence and photoluminescence measurements reveal an emission in the range 1.40–1.52 eV related with the spatial localization of the charge carriers at the interfaces of the two crystalline phases. Mg related emission is evidenced by cathodoluminescence performed on the GaAs epilayer. However, no direct evidence for a Mg related emission is found for the nanowires. The excitation power dependency on both peak energy and intensity of the photoluminescence gives a clear evidence for the type II nature of the radiative transitions. From the temperature dependence on the photoluminescence intensity, non-radiative de-excitation channels with different activation energies were found. The fact that the estimated energies for the escape of the electron are higher in the nanowires grown on Si(111) suggests the presence of wider zinc-blende segments.
Authors:
; ;  [1] ;  [2] ; ; ;  [3] ;  [4] ; ; ;  [5]
  1. Departamento de Física, I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal)
  2. Laboratório Central de Análises, Universidade de Aveiro, 3810-193 Aveiro (Portugal)
  3. Departamento de Ciencia de los Materiales e IM y QI, F. Ciencias, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)
  4. Solid State Physics, The Nanometer Consortium, Box 118, Lund University, Lund SE-22100 (Sweden)
  5. Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, Minas Gerais (Brazil)
Publication Date:
OSTI Identifier:
22259297
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACTIVATION ENERGY; CATHODOLUMINESCENCE; CHARGE CARRIERS; DE-EXCITATION; DOPED MATERIALS; EXCITATION; GALLIUM ARSENIDES; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; QUANTUM WIRES; SUBSTRATES; TEMPERATURE DEPENDENCE; WIRES; ZINC SULFIDES