Effects of the deposition conditions of p-type hydrogenated nanocrystalline cubic silicon carbide on n-type crystalline silicon heterojunction solar cell performance

P-type hydrogenated nanocrystalline cubic silicon carbide (p-nc-3C-SiC:H) is a promising material for the window layer due to its wider bandgap of 2.2 eV and lower light absorption than conventional p-a-Si:H to reduce light absorption loss in the range of 400-600 nm. However, since large amount of atomic hydrogen is generated under the deposition condition of p-nc-3C-SiC:H by VHF-PECVD, it gives damage to the surface of the n-c-Si by etching. In this study, we investigated the effects of deposition conditions of p-nc-3C-SiC:H on the properties of n-type c-Si heterojunction solar cells with the structure of Al/Ag/ITO/p-nc-3C-SiC:H/a-Si_1-xC_x:H/n-c-Si/n-a-Si:H/Al. It was found that it is needed to keep higher deposition rate to avoid etching of an a-Si_1-xC_x:H buffer layer, which is a passivation layer and protective layer against atomic hydrogen etching of the crystalline silicon surface. At high deposition pressure of 800 Pa, we successfully deposited p-nc-3C-SiC:H films at higher deposition rate without the degradation of the electrical property. Under the optimized conditions, high efficiency of 17.0 % (V_oc = 0.638 V, J_sc = 35.95 mA/cm², Fill factor = 0.742) was achieved without any anti-reflection layers and textures.