Fabrication of Cu(In,Ga)Se2 thin films by ion beam sputtering deposition from a quaternary target at different substrate temperatures

Abstract

Cu(In, Ga)Se2 (CIGS) thin films were fabricated by ion beam sputtering deposition from a single quaternary target at different substrate temperatures (Tsub). The thin films were characterized with X-ray diffractometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and four-point probe technique to study the microstructures, surface morphology, composition and electrical properties, respectively. The results show that the films grown above 400 °C are of chalcopyrite structure. Cu(In0.7Ga0.3)Se2 thin film was obtained when Tsub is 550 °C. The Cu and Se atomic percentage when Tsub is above 500 °C is higher than when Tsub is below 500 °C. With the increase in Tsub, the surfaces morphology of the films is denser and the resistivity of the films decreases.