Characterization of microcrystalline silicon thin film solar cells prepared by high working pressure plasma-enhanced chemical vapor deposition

Abstract

Using the high working pressure plasma-enhanced chemical vapor deposition (HWP-PECVD) technique, the hydrogenated microcrystalline silicon (mu c-Si:H) films for photovoltaic layers of thin film solar cells was investigated. The mu c-Si:H films were deposited on surface textured fluorine-doped tin oxide (FTO) glass substrates at 100 Torr in a 100 MHz very high frequency (VHF) plasma of gas mixtures containing He, H-2, and SiH4. It was found that an optimum ratio of the H-2/SiH4 flow-rate existed for growing a homogenous microcrystalline through the whole film without amorphous incubation layer. When an intrinsic mu c-Si:H thin film was deposited at n-i-p single junction solar cell, the cell performances were dependent on with or without an amorphous incubation layer. With an amorphous incubation layer, the open circuit voltage (V (oc) ) of cell was 0.8 V, which was typical cell property of hydrogenated amorphous silicon (a-Si:H). On the other hand, at the optimum ratio of the H-2/SiH4 flow-rate, mu c-Si:H single cell responding an infrared light showed the V (oc) of 0.4 V.