Spectroscopic Evidence for a Surface Layer in CuInSe2:Cu Deficiency
The near-surface region of thin-film polycrystalline (PX) CuIn{sub 1-x}Ga{sub x}Se{sub 2} (CIGS) is considered important because it is the region where the electrical junction forms in a CIGS photovoltaic device. Spectroscopic ellipsometry measurements of polycrystalline CuInSe{sub 2} films reveal that there is a thin layer at the surface which has different optical and electronic properties from those of the bulk film. This surface layer of thin-film CIGS has a larger band gap and greater spin-orbit interaction energy than the bulk film. These properties indicate that the surface layer is more Cu deficient than the bulk in the nearly stoichiometric thin-film PX-CIGS used in photovoltaic devices. This work provides an insight into the importance of surface layer engineering for photovoltaic device design.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-99GO10337
- OSTI ID:
- 941435
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 2, 2007 Vol. 91; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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