High figure-of-merit p-type transparent conductor, Cu alloyed ZnS via radio frequency magnetron sputtering

P-Type transparent conducting Cu alloyed ZnS thin films from CuZnS targets (, 0.2, 0.3, 0.4, and 0.5) were deposited on glass substrates via radio frequency sputtering. X-ray diffraction and TEM-SAED analysis show that all the films have sphalerite ZnS as the majority crystalline phase. In addition, films with 30% and 40% Cu show the presence of increasing amounts of crystalline Cu2S phase. Conductivity values 400 S were obtained for the films having 30% and 40% Cu, with the maximum conductivity of 752 S obtained for the film with 40% Cu. Temperature dependent electrical transport measurements indicate metallic as well as degenerate hole conductivity in the deposited films. The reflection-corrected transmittance of this Cu alloyed ZnS (40% Cu) film was determined to be 75% at 550 nm. The transparent conductor figure of merit () of the Cu alloyed ZnS (40% Cu), calculated with the average value of transmittance between 1.5 to 2.5 eV, was ≈276