Science and technology of amorphous silicon alloy photovoltaics

Significant advances have been made in our understanding of amorphous silicon alloy materials and solar cells that have resulted in the achievement of high cell and module efficiency. The R&D results have also been translated to production, and several manufacturers have expanded their production capacity, raising the worldwide annual capacity exceeding 25 MW. In this paper, we shall review the progress in the science and technology of amorphous silicon alloy photovoltaics and discuss the future directions.