Substrate temperature effect on the optical properties of radio-frequency sputtered CuInSe2 thin films

Abstract

The influence of growth temperature on the optical properties of CuInSe2 thin films producing sputtering targets of different compositions is presented. CuInSe2 films exhibited direct allowed transitions with values ranging between 0.9 and 1 eV depending on substrate temperature. Additional direct forbidden transitions, ranging between 1 and 1.22 eV, are also observed. A clear correlation is observed between crystallinity and optical gap. On the other hand, film composition, in the range analyzed, did not show influence over optical properties.