Thickness dependent electrical and optical properties of nanocrystalline copper sulphide thin films grown by simple chemical route

A Novel chemical bath deposition (CBD) method has been developed to deposit semiconducting nanocrystalline copper sulphide (Cu(2)S) thin films on ordinary glass substrates with different thicknesses. The deposition bath consists of aqueous copper chloride (CuCl(2)), ammonia (NH(3)) and thiourea [SC(NH(2))2]. It is found that the deposition parameters significantly influence the quality and the thickness of Cu(2)S films. The films were uniform and adherent to glass substrates. The deposited films have been characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), optical absorption and electrical resistivity. The effect of film thickness on the optical, structural and electrical properties has been studied. The shift of 0.46 eV in the optical band gap energy (E(g)) and decrease in electrical resistivity from 6.463x10(-2) to 8.973x10(-3) Omega -cm and increase in the grain size of Cu(2)S crystallites from 30 to 250 nm were observed when the film thickness was varied from 130 to 250 nm.