Window p-layer in amorphous pin solar cells using ZnO as Transparent Conductive Oxide

•Optimization of a-Si p-layers in record MICROMORPH™ modules.•Improvement of material quality by using 16 mm gap reactor.•Reduction of contamination by soft deposition and increased total gas flow.

The main steps of p-layer development in pin thin film amorphous silicon solar cell at TEL Solar are presented. First, the implementation of a new PECVD reactor is shown to contribute to an improvement in amorphous silicon carbide (a-SiC) p-layer quality probably by reducing the porosity and leading to an increased open circuit voltage after the solar cell is subjected to light soaking. Second, an alternative high flow deposition regime for the p-doped a-SiC layer was successfully developed improving the layer purity and electrical conductivity. And third, a softer deposition regime for the very first part of the p-layer, the contact layer, which plays a crucial role in the release of Zn from the TCO, contributes to a decreased overall Zn contamination.