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Structural and Optical Properties of Highly Efficient 2- μm Thick CdS/CdTe Thin Film Solar Cells

Published online by Cambridge University Press:  21 March 2011

K. Nakamura
Affiliation:
Department of Physical Science, Graduate School of Engineering Science, −Osaka University Toyonaka, Osaka, 560-8531, Japan
M. Gotoh
Affiliation:
Department of Physical Science, Graduate School of Engineering Science, −Osaka University Toyonaka, Osaka, 560-8531, Japan
T. Fujihara
Affiliation:
Department of Physical Science, Graduate School of Engineering Science, −Osaka University Toyonaka, Osaka, 560-8531, Japan
T. Toyama
Affiliation:
Department of Physical Science, Graduate School of Engineering Science, −Osaka University Toyonaka, Osaka, 560-8531, Japan
H. Okamoto
Affiliation:
Department of Physical Science, Graduate School of Engineering Science, −Osaka University Toyonaka, Osaka, 560-8531, Japan
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Abstract

The structural and optical properties of CdS/CdTe(S) interface region of 2-μm thick CdS/CdTe solar cells have been studied in conjunction with photovoltaic performances of the solar cells. The properties are found to be crucially influenced by the annealing temperature and oxygen concentration of the CdCl2 treatment. An increase in VOC and F.F. found in the solar cells with the CdCl2 treatment at < 360°C is interpreted as due to suppression of interdiffusion of sulfur and tellurium at the CdS/CdTe(S) interface. On the other hand, the electromodulated photoluminescence with UV light excitation (UVE-EMPL) study reveals that the increasing VOC due to increasing oxygen concentration to 5% is likely to be caused by an increase in the built-in electric field in n+-CdTe1−xSx just adjacent to the CdS/CdTe(S) interface. As a result of the modification of the process parameters, we have achieved the conversion efficiency of 13.6% (VOC: 0.817V, JSC: 23.0 mA/cm2, F.F.: 0.725) using 2.3-μm thick PV active layer without anti-reflection coating.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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