Electronic structure of pure and doped cuprous oxide with copper vacancies: Suppression of trap states

Leah Y. Isseroff, Emily A. Carter

Research output: Contribution to journalArticle

58 Scopus citations

Abstract

Cuprous oxide (Cu2O) is an attractive material for solar energy applications, but its photoconductivity is limited by minority carrier recombination caused by native defect trap states. We examine the creation of trap states by cation vacancies, using first principles calculations based on density functional theory (DFT) to analyze the electronic structure and calculate formation energies. With several DFT-based methods, a simple vacancy is predicted to be consistently more stable than a split vacancy by 0.21 ± 0.03 eV. Hybrid DFT is used to analyze the density of states and charge density distribution, predicting a delocalized hole for the simple vacancy and a localized hole for the split vacancy, in contrast to previously reported results. The differing character of the two defects indicates that they contribute to conduction via different mechanisms, with the split vacancy as the origin of the acceptor states that trap minority carriers. We explore methods of improving photoconductivity by doping Cu2O with Li, Mg, Mn, and Zn, analyzing their impact on vacancy formation energies and electronic structures. Results suggest that the Li dopant has the greatest potential to improve the photoconductivity of the oxide by inhibiting the creation of trap states.

Original languageEnglish (US)
Pages (from-to)253-265
Number of pages13
JournalChemistry of Materials
Volume25
Issue number3
DOIs
StatePublished - Feb 12 2013

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Keywords

  • CuO
  • density functional theory
  • doping
  • photoconductivity
  • solar energy
  • trap states
  • vacancy formation energy

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