Dark Conductivity Peak in P-Type Glow-Discharged a-SiC:H Films

Here we report he doping characteristics of a-SiC:H, specifically the dark conductivity peak of P-type a-SiC:H. When the CH4 concentration in the gas rhixture of Sill4, CH4 and B2H ~ was varied under constant B2H ~ concentration, a clear dark-conductivity peak was observed for glow-discharged a-SiC:H film at nearly 20 % of CH4. The peak becomes clearer below 0.5 % of B2H ~ in the gas mixture. We have not yet seen this feature reported in the literature. No peak is observed for undoped and phosphorus-doped a-SiC:H. Efforts to develop the high efficiency photovoltaic a-Si solar cells are being made at many laboratories. a-SiC:H (1, 2) is used on the light incident side as a wide bandgap material for a high efficiency a-Si solar cells. Recently, efficiencies above 8 % have been ob-tained by using this material (3, 4). We are also study-ing the material. The glow-discharge method is used to prepare a-SiC:H and CH4 is used as the carbon source