Influence of CH4 flow rate on properties of HF-PECVD a-SiC films and solar cell application

The hydrogenated amorphous silicon carbide (a-SiC:H) alloy is one of the more intensively studied as it has importance as an active layer in photovoltaic cells (as p-type window layer). In this present, a wide band gap and highly conductive p-type a-SiC:H thin films have been deposited by high-frequency plasma-enhanced chemical vapor deposition at low substrate temperature of 150 °C. This material as a window layer application for amorphous silicon solar cells has carry out. The a-SiC:H thin films were deposited at a plasma excitation frequency of 27.13 MHz by varying the dilution of CH4 + H2 mixture in the reaction chamber. The effects of deposited parameters on the characteristics of a-SiC:H have been investigated by UV–VIS spectroscopy, dark- and photoconductivity measurement, scanning electron microscopy and second ion mass spectroscopy, respectively. The results show the properties of a-SiC:H films as a function of carbon content. It was found that a-SiC:H film deposited at CH4 flow rate of 40 sccm and H2 flow rate of 50 sccm is better suited for thin film solar cell application and the solar cell with conversion efficiency of 10.11% was obtained.

► We present a wide band gap and highly conductive p-type a-SiC:H thin films by high-frequency plasma enhanced chemical vapor deposition at low substrate temperature of 150 °C.
► The effects of the CH4 flow rate on properties of a-SiCx:H films are investigated.
► It was found that a-SiC:H film deposited at CH4 flow rate of 40 sccm and H2 flow rate of 50 sccm is better suited for thin film solar cell application.
► We achieve the thin film solar cells with efficiency of 10.1%.