Amorphous silicon passivation applied to the front side boron emitter of n-type silicon solar cells

Hydrogenated amorphous silicon (a-Si:H) was used to passivated the front side boron emitter of n-type silicon solar cells. The main aspect was to investigate the parasitic absorption behavior of the a-Si:H layers on the solar cells front side with different thicknesses between 5 nm and 20 nm. Therefore planar solar cells featuring a diffused boron emitter and a diffused back surface field were fabricated. The cells reached energy conversion efficiencies up to 17.8% with an open- circuit voltage VOC of 641 mV for an a-Si:H thickness of 15 nm. Analogous processed reference cells, with an Al2O3 passivated emitter achieved an efficiency of 19% and a VOC of 658 mV.