Electrical and Optical Properties of Stannite-Type Quaternary Semiconductor Thin Films

Quaternary stannite-type semiconductor films of Cu2CdSnS4 and Cu2ZnSnS4 with (112) orientation were deposited on heated glass substrates using atom beam sputtering. These p-type films showed resistivities which were decreasing functions of the substrate temperature up to 240°C. The films had an absorption coefficient larger than 1 × 104 cm-1 in the visible wavelength range. The direct optical band gaps of the (112) oriented polycrystalline films were estimated as 1.06 eV and 1.45 eV for Cu2CdSnS4 and Cu2ZnSnS4, respectively.