Thin film preparation and characterization of wide band gap Cu3TaQ4 (Q = S or Se) p-type semiconductors

The structural, optical, and electronic properties of thin films of a family of wide band gap (Eg > 2.3 eV) p-type semiconductors Cu3TaQ4 (Q = S or Se) are presented. Thin films prepared by pulsed laser deposition of ceramic Cu3TaQ4 targets and ex-situ annealing of the as-deposited films in chalcogenide vapor exhibit mixed polycrystalline/[100]-directed growth on amorphous SiO2 substrates and strong (100) preferential orientation on single-crystal yttria-stabilized zirconia substrates. Cu3TaS4 (Eg = 2.70 eV) thin films are transparent over the entire visible spectrum while Cu3TaSe4 (Eg = 2.35 eV) thin films show some absorption in the blue. Thin film solid solutions of Cu3TaSe4 − xSx and Cu3TaSe4 − xTex can be prepared by annealing Cu3TaSe4 films in a mixed chalcogenide vapor. Powders and thin films of Cu3TaS4 exhibit visible photoluminescence when illuminated by UV light.