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Title: Investigation of optical transitions in InAs/GaAs(Sb)/AlAsSb quantum dots using modulation spectroscopy

InAs quantum dots (QDs) were grown in an AlAs{sub 0.56}Sb{sub 0.44}/GaAs matrix in the unintentionally doped (uid) region of an In{sub 0.52}Al{sub 0.48}As solar cell, establishing a variety of optical transitions both into and out of the QDs. The ultimate goal is to demonstrate sequential absorption, where one photon is absorbed, promoting an electron from the valence band into the QD, and a second photon is absorbed in order to promote the trapped electron from a QD state into the host conduction band. In this study, we directly investigate the optical properties of the solar cell using photoreflectance and evaluate the possibility of sequential absorption by measuring spectral responsivity with broadband infrared illumination.
Authors:
; ; ;  [1] ; ; ;  [2]
  1. Nanopower Research Laboratories, Rochester Institute of Technology, Rochester, New York 14623 (United States)
  2. University of California at Los Angeles, Los Angeles, California 90095 (United States)
Publication Date:
OSTI Identifier:
22395595
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 25; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ABSORPTION; ABSORPTION SPECTROSCOPY; ALUMINIUM ARSENIDES; ANTIMONIDES; DOPED MATERIALS; GALLIUM ARSENIDES; ILLUMINANCE; INDIUM ARSENIDES; MODULATION; OPTICAL PROPERTIES; PHOTONS; QUANTUM DOTS; SOLAR CELLS; TRAPPED ELECTRONS; VALENCE