Highly conductive GaN anti-reflection layer at transparent conducting oxide/Si interface for silicon thin film solar cells

Highly conductive GaN film was prepared by magnetron sputtering and this was applied as an anti-reflection layer (ARL) between a transparent conducting oxide and microcrystalline silicon (μc-Si:H) in order to decrease optical reflection. The efficiency (8.81%) of μc-Si:H single junction thin film solar cell with the proposed GaN ARL exceeded that of the cell (8.36%) with the widely used TiO2/ZnO bilayer ARL. Moreover, the proposed GaN ARL requires no protection layer against hydrogen plasma such as ZnO overcoating (∼10 nm) in case of the TiO2/ZnO bilayer. GaN ARL can replace the TiO2/ZnO bilayer ARL in terms of high performance and simple fabrication process.