Copper Sulfides Thin Films With Controlled Properties for Photovoltaic Cells

Films of Cu x S with 430-700 nm thickness were deposited by robotic spray pyrolysis technique, at T = 300ºC, using 90 spraying sequences, from water:ethanol:glycerol = 7:2:1 (in volumes) solutions with a molar ratio Cu:S = 1:2.5-3.5.Relative dense, homogenous and uniform films of Cu x S (x = 1.8-2), with E g = 1.97-2.49eV and exhibiting electric resistance behavior were obtained.The as-deposited films were annealed in air or in sulfur atmosphere, at 300 ºC, for one hour.Dense and uniform films, containing Cu 2 S crystalline phase, with E g = 2.16 eV and p-type semiconductor electrical behavior, were obtained by annealing in air of films deposited from precursors' solutions with Cu:S = 1:3 at Cu 2+ concentration of 3.5 mol/L.