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Title: First-principles study of direct and narrow band gap semiconducting β -CuGaO2

Semiconducting oxides have attracted much attention due to their great stability in air or water and the abundance of oxygen. Recent success in synthesizing a metastable phase of CuGaO2 with direct narrow band gap opens up new applications of semiconducting oxides as absorber layer for photovoltaics. Using first-principles density functional theory calculations, we investigate the thermodynamic and mechanical stabilities as well as the structural and electronic properties of the β-CuGaO2 phase. Our calculations show that the β-CuGaO2 structure is dynamically and mechanically stable. The energy band gap is confirmed to be direct at the Γ point of Brillouin zone. In conclusion, the optical absorption occurs right at the band gap edge and the density of states near the valance band maximum is large, inducing an intense absorption of light as observed in experiment.
Authors:
 [1] ;  [1] ;  [1] ;  [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
Publication Date:
OSTI Identifier:
1249337
Report Number(s):
IS-J--8947
Journal ID: ISSN 2053-1591
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Materials Research Express (Online)
Additional Journal Information:
Journal Name: Materials Research Express (Online); Journal Volume: 2; Journal Issue: 4; Journal ID: ISSN 2053-1591
Publisher:
IOP Publishing
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE