Nanostructured silicon p-layer obtained by radio frequency power profiling process for high-efficiency amorphous silicon solar cell

• A RF power profiling process was developed to fabricate nc-Si:H p-layer.
• Wide bandgap, low ion damage, appropriate bandgap matching can be easily obtained.
• The maximum Voc for pure a-Si:H cell is 0.998 V.
• Up to now the best efficiency for a-Si:H cell is 10.8%.

A RF power profiling process has been developed to efficiently grow nanostructured silicon (nc-Si:H) p-layers for high-efficiency amorphous silicon solar cells. The p-layer deposition starts at a relatively low power in the initial stage, which is then continuously and rapidly increased to a high level until the bulk p-layer deposition is finished. Incorporating the p-layer into a-Si:H solar cell resulted in high Voc and high FF simultaneously, which can be ascribed to the reduced recombination at the i/p interface caused by the suitable band-gap of p-layer, low ion damage to i/p interface, and appropriate band-gap matching between p- and i-layers during the RF power profiling process. An initial efficiency of 10.8% for an a-Si:H solar cell with both high Voc of 0.99 V and high FF of 0.72 was obtained. This power profiling scheme is potentially advantageous since it is easier to integrate into continuous process.