This paper presents a detailed study on the effects of carbon incorporation and substrate temperature on structural, optical, and electrical properties of p-type nanocrystalline amorphous silicon films. A p-nc-SiC：H thin film with optical gap of 1.92eV and activation energy of 0.06eV is obtained through optimizing the plasma parameters. By using this p-type window layer, single junction diphasic nc-SiC：H /a-Si：H solar cells have been successfully prepared with a Voc of 0.94eV.