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MoOx as an Efficient and Stable Back Contact Buffer for Thin Film CdTe Solar Cells

Published online by Cambridge University Press:  15 June 2012

Hao Lin ,
Wei Xia ,
Hsiang N. Wu ,
Ching W. Tang ,
Irfan Irfan  and
Yongli Gao
Hao Lin
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Wei Xia
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Hsiang N. Wu
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Ching W. Tang
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Irfan Irfan
Affiliation:
Department of Physics and Astronomy, University of Rochester, Rochester, NY, 14627
Yongli Gao
Affiliation:
Department of Physics and Astronomy, University of Rochester, Rochester, NY, 14627
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Abstract

A low-resistance back contact for n-CdS/p-CdTe solar cells has been developed, which utilizes a thermally evaporated MoOx thin film as the buffer layer between the p-CdTe and the back electrode. The low-resistance behavior of back contact is attributed to the high work function of MoOx, which reportedly is as high as 6.8 eV, and thus adequately matches that of p-CdTe. With MoOx as the buffer, a variety of common metals, even those with a low work function such as Al, have been found to be useful as the electrode in forming the back contact. Other advantages of the MoOx buffer include dry application by vacuum deposition, and thus it is particularly suitable for the fabrication of ultra-thin CdTe solar cells without introducing additional shorting defects. Surface cleaning of CdTe films prior to MoOx deposition has also been studied. The cell stability has been evaluated through thermal annealing tests. Thermal degradation has been explained in terms of oxidation of the metal electrodes. CdTe cells with high efficiency and good stability have been demonstrated with MoOx as the back contact buffer and Ni as the electrode.

Keywords

thin filmscanning electron microscopy (SEM)photovoltaic
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1447: Symposium V – Nanostructured and Advanced Materials for Solar-Cell Manufacturing , 2012 , mrss12-1447-v02-09
Copyright
Copyright © Materials Research Society 2012

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