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Title: Period-doubling reconstructions of semiconductor partial dislocations

Atomic-scale understanding and control of dislocation cores is of great technological importance, because they act as recombination centers for charge carriers in optoelectronic devices. Using hybrid density-functional calculations, we present period-doubling reconstructions of a 90° partial dislocation in GaAs, for which the periodicity of like-atom dimers along the dislocation line varies from one to two, to four dimers. The electronic properties of a dislocation change drastically with each period doubling. The dimers in the single-period dislocation are able to interact, to form a dispersive one-dimensional band with deep-gap states. However, the inter-dimer interaction for the double-period dislocation becomes significantly reduced; hence, it is free of mid-gap states. The Ga core undergoes a further period-doubling transition to a quadruple-period reconstruction induced by the formation of small hole polarons. Lastly, the competition between these dislocation phases suggests a new passivation strategy via population manipulation of the detrimental single-period phase.
 [1] ;  [2] ;  [1] ;  [3] ;  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States); DGIST, Daegu (Korea)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1884-4057
Grant/Contract Number:
Accepted Manuscript
Journal Name:
NPG Asia Materials (Online)
Additional Journal Information:
Journal Name: NPG Asia Materials (Online); Journal Volume: 7; Journal Issue: 9; Related Information: NPG Asia Materials; Journal ID: ISSN 1884-4057
Nature Publishing Group Asia
Research Org:
NREL (National Renewable Energy Laboratory (NREL), Golden, CO (United States))
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS gallium arsenide; dislocations; reconstruction; ab initio calculations; deep levels; passivation