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Title: Photocapacitance study of type-II GaSb/GaAs quantum ring solar cells

In this study, the density of states associated with the localization of holes in GaSb/GaAs quantum rings are determined by the energy selective charging of the quantum ring distribution. The authors show, using conventional photocapacitance measurements, that the excess charge accumulated within the type-II nanostructures increases with increasing excitation energies for photon energies above 0.9 eV. Optical excitation between the localized hole states and the conduction band is therefore not limited to the Γ(k = 0) point, with pseudo-monochromatic light charging all states lying within the photon energy selected. The energy distribution of the quantum ring states could consequently be accurately related from the excitation dependence of the integrated photocapacitance. The resulting band of localized hole states is shown to be well described by a narrow distribution centered 407 meV above the GaAs valence band maximum.
Authors:
;  [1] ; ;  [2]
  1. Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)
  2. Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)
Publication Date:
OSTI Identifier:
22271296
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 1; 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; 77 NANOSCIENCE AND NANOTECHNOLOGY; ELECTRONIC STRUCTURE; ENERGY SPECTRA; ENERGY-LEVEL DENSITY; EXCITATION; GALLIUM ANTIMONIDES; GALLIUM ARSENIDES; HOLES; MONOCHROMATIC RADIATION; NANOSTRUCTURES; PHOTONS; SOLAR CELLS; VALENCE; VISIBLE RADIATION