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Author Wu, X. ♦ Asher, S. ♦ Levi, D. H. ♦ King, D. E. ♦ Yan, Y. ♦ Gessert, T. A. ♦ Sheldon, P.
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword SOLAR ENERGY ♦ ADHESION ♦ ALLOYS ♦ BUFFERS ♦ CURRENT DENSITY ♦ EFFICIENCY ♦ FABRICATION ♦ PERFORMANCE ♦ QUANTUM EFFICIENCY ♦ SOLAR CELLS ♦ WAVELENGTHS
Abstract In this work, we found that the interdiffusion of the CdS and Zn{sub 2}SnO{sub 4} (ZTO) layers can occur either at high temperature (550--650{sup o}C) in Ar or at lower temperature (400--420{sup o}C) in a CdCl{sub 2} atmosphere. By integrating a Zn{sub 2}SnO{sub 4} film into a CdS/CdTe solar cell as a buffer layer, this interdiffusion feature can solve several critical issues and improve device performance and reproducibility of both SnO{sub 2}-based and Cd{sub 2}SnO{sub 4}-based CdTe cells. Interdiffusion consumes the CdS film from both the ZTO and CdTe sides during the device fabrication process and improves quantum efficiency at short wavelengths. The ZTO film acts as a Zn source to alloy with the CdS film, which results in increases in the band gap of the window layer and in short-circuit current density J{sub sc}. Interdiffusion can also significantly improve device adhesion after CdCl{sub 2} treatment, thus providing much greater process latitude when optimizing the CdCl{sub 2} process step. The optimum CdCl{sub 2}-treated CdTe device has high quantum efficiency at long wavelength, because of its good junction properties and well-passivated CdTe film. We have fabricated a Cd{sub 2}SnO{sub 4}/Zn{sub 2}SnO{sub 4}/CdS/CdTe cell demonstrating an NREL-confirmed total-area efficiency of 15.8% (V{sub oc}=844.3mV, J{sub sc}=25.00mA/cm{sup 2}, and fill factor=74.82%). This high-performance cell is one of the best thin-film CdTe solar cells in the world.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-04-15
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 89
Issue Number 8


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