Period-Doubling Reconstructions of Semiconductor Partial Dislocations

Ji Sang Park, Bing Huang, Su Huai Wei, Joongoo Kang, William E. McMahon

Research output: Contribution to journalArticlepeer-review

14 Scopus Citations

Abstract

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. The competition between these dislocation phases suggests a new passivation strategy via population manipulation of the detrimental single-period phase.

Original languageAmerican English
Article numbere216
Number of pages6
JournalNPG Asia Materials
Volume7
Issue number9
DOIs
StatePublished - 11 Sep 2015

Bibliographical note

Publisher Copyright:
© 2015 Nature Publishing Group All rights reserved.

NREL Publication Number

  • NREL/JA-5J00-63881

Keywords

  • ab initio calculations
  • deep levels
  • dislocations
  • gallium arsenide
  • passivation
  • reconstruction

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