Electronic and atomic structure of complex defects in Al- and Ga-highly doped ZnO films

Menéndez Proupin, Eduardo and Palacios Clemente, Pablo and Wahnon Benarroch, Perla (2015). Electronic and atomic structure of complex defects in Al- and Ga-highly doped ZnO films. "Materials Chemistry and Physics", v. 160 ; pp. 420-428. ISSN 0254-0584. https://doi.org/10.1016/j.matchemphys.2015.05.012.

Description

Title: Electronic and atomic structure of complex defects in Al- and Ga-highly doped ZnO films
Author/s:
  • Menéndez Proupin, Eduardo
  • Palacios Clemente, Pablo
  • Wahnon Benarroch, Perla
Item Type: Article
Título de Revista/Publicación: Materials Chemistry and Physics
Date: June 2015
ISSN: 0254-0584
Volume: 160
Subjects:
Faculty: E.T.S. de Ingeniería Aeronáutica y del Espacio (UPM)
Department: Física Aplicada a las Ingenierías Aeronáutica y Naval
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Point defects in Ga- and Al-doped ZnO thin films are studied by means of first principles electronic structure calculations. Candidate defects are identified to explain recently observed differences in electrical and spectroscopical behavior of both systems. Substitutional doping in Ga-ZnO explain the metallic behavior of the electrical properties. Complexes of interstitial oxygen with substitutional Ga can behave as acceptor and cause partial compensation, as well as gap states below the conduction band minimum as observed in photoemission experiments. Zn vacancies can also act as compensating acceptors. On the other hand, the semiconducting behavior of Al-ZnO and the small variation in the optical gap compared with pure ZnO, can be explained by almost complete compensation between acceptor Zn vacancies and substitutional Al donors. Interstitial Al can also be donor levels and can be the origin of the small band observed in photoemission experiments below the Fermi level. Combinations of substitutional Al with interstitial oxygen can act simultaneously as compensating acceptor and generator o the mentioned photoemission band. The theoretical calculations have been done using density functional theory (DFT) within the generalized gradient approximation with onsite Coulomb interaction. In selected cases, DFT calculations with semilocal-exact exchange hybrid functionals have been performed. Results explain photoelectron spectra of Ga-ZnO and Al-ZnO at the corresponding doping levels.

Funding Projects

TypeCodeAcronymLeaderTitle
FP7269279NANOCISUnspecifiedDevelopment of a new generation of CIGS-based solar cells

More information

Item ID: 40991
DC Identifier: http://oa.upm.es/40991/
OAI Identifier: oai:oa.upm.es:40991
DOI: 10.1016/j.matchemphys.2015.05.012
Official URL: http://www.sciencedirect.com/science/article/pii/S0254058415300729
Deposited by: Memoria Investigacion
Deposited on: 30 Sep 2016 11:25
Last Modified: 06 Jun 2019 12:53
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