Wide band-gap, fairly conductive p-type hydrogenated amorphous silicon carbide films prepared by direct photolysis; solar cell application

Abstract

Wide optical band-gap (2.0–2.3 eV) undoped and boron-doped hydrogenated amorphous silicon carbide (a-SiC:H) films have been prepared by both direct photo and rf glow discharge (GD plasma) decomposition of pure methylsilanes or acetylene and disilane gas mixtures. The photochemically prepared p-type films showed higher dark conductivities and lower activation energies. For an optical band gap of 2.0 eV a high conductivity of 7.0×10−5 (S cm−1) and a low activation energy of 0.33 eV have been measured. The first trial of these wide band-gap, fairly conductive films as a window layer in a p-i-n solar cell showed the high conversion efficiency of 9.46% under AM1 insolation.