UV nanoimprint for the replication of etched ZnO:Al textures applied in thin‐film silicon solar cells

In this work, we present a technology for a high precision nanostructure replication process based on ultraviolet nanoimprint lithography for the application in the field of thin-film photovoltaics. The potential of the technology is demonstrated by the fabrication of microcrystalline silicon thin-film prototype solar cells. The high accuracy replication of random microstructures made from sputtered and etched ZnO:Al, used to scatter the incident light in thin solar cells, is shown by local topography investigations of the same 7.5 × 7.5 µm2 area on the master and the replica. Different types of imprint resists and imprint moulds were investigated to find the optimal, high precision replication technology. Two types of thin-film silicon solar cells, in p-i-n and n-i-p configuration, were fabricated to study the potential of the imprint technology for different applications. It is shown that solar cells deposited on an imprinted glass hold similar performances compared with reference solar cells fabricated with a standard process on textured ZnO:Al. Thus, it is demonstrated that the replication of light scattering structures by using an imprint process is an attractive method to decouple the scattering properties from the layer forming the electrical front contact. Because a simple and cheap high throughput process is used, this study additionally proves the relevance for the industrial mass production in the field of photovoltaics. Copyright © 2013 John Wiley & Sons, Ltd.

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