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Electrical properties of the CdTe back contact: A new chemically etching process based on nitric acid/acetic acid mixtures

Han, Junfeng and Fan, Chunjie and Spanheimer, Christina and Fu, Ganhua and Zhao, Kui and Klein, Andreas and Jaegermann, Wolfram (2010):
Electrical properties of the CdTe back contact: A new chemically etching process based on nitric acid/acetic acid mixtures.
In: Applied Surface Science, 256, pp. 5803-5806. ISSN 01694332,
[Article]

Abstract

The performance of the back contact is one of the major issues of CdTe solar cell research. Standard nitric-phosphric (NP) acid chemical etching before metallization is widely used to improve contact formation. However, previous studies of this traditional etching method indicated a blocking Shottky barrier at the back contact, and a roll-over phenomenon was found in the J-V curves of the CdTe solar cells. In this work, a new etching solution, i.e., a nitric-acetic (NA) acid was employed. The etching rate was slow and a Te rich layer was formed on the surface, which was less than 1 nm. The CdTe solar cell with this new etching method showed no roll-over phenomenon and displayed a good ohmic back contact performance. XPS analysis demonstrated that the back contact barrier height was close to those of CdTe with standard NP etching. A possible mechanism was presented for the improvement of back contact properties.

Item Type: Article
Erschienen: 2010
Creators: Han, Junfeng and Fan, Chunjie and Spanheimer, Christina and Fu, Ganhua and Zhao, Kui and Klein, Andreas and Jaegermann, Wolfram
Title: Electrical properties of the CdTe back contact: A new chemically etching process based on nitric acid/acetic acid mixtures
Language: English
Abstract:

The performance of the back contact is one of the major issues of CdTe solar cell research. Standard nitric-phosphric (NP) acid chemical etching before metallization is widely used to improve contact formation. However, previous studies of this traditional etching method indicated a blocking Shottky barrier at the back contact, and a roll-over phenomenon was found in the J-V curves of the CdTe solar cells. In this work, a new etching solution, i.e., a nitric-acetic (NA) acid was employed. The etching rate was slow and a Te rich layer was formed on the surface, which was less than 1 nm. The CdTe solar cell with this new etching method showed no roll-over phenomenon and displayed a good ohmic back contact performance. XPS analysis demonstrated that the back contact barrier height was close to those of CdTe with standard NP etching. A possible mechanism was presented for the improvement of back contact properties.

Journal or Publication Title: Applied Surface Science
Journal volume: 256
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Surface Science
Date Deposited: 29 Oct 2011 08:06
Additional Information:

Material- und Geowissenschaften

Identification Number: doi:10.1016/j.apsusc.2010.01.087
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