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Title: Deep Subgap Feature in Amorphous Indium Gallium Zinc Oxide. Evidence Against Reduced Indium

Amorphous indium gallium zinc oxide (a-IGZO) is the archetypal transparent amorphous oxide semiconductor. In spite of the gains made with a-IGZO over amorphous silicon in the last decade, the presence of deep subgap states in a-IGZO active layers facilitate instabilities in thin film transistor properties under negative bias illumination stress. Several candidates could contribute to the formation of states within the band gap. We present evidence against In+ lone pair active electrons as the origin of the deep subgap features. No In+ species are observed, only In0 nano-crystallites under certain oxygen deficient growth conditions. Our results further support under coordinated oxygen as the source of the deep subgap states.
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  1. Binghamton Univ., NY (United States)
  2. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1862-6300
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physica Status Solidi. A, Applications and Materials Science; Journal Volume: 212; Journal Issue: 7
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE amorphous materials; lnGaZnO; transmission electron microscopy; transparent conductive oxides; work function; X-ray spectroscopy