Preparation and characterization of flash-evaporated CuInSe 2/CuGaSe 2 thin films

Abstract

Deposition of CuInSe 2 thin film on CuGaSe 2 thin film (CuInSe 2/CuGaSe 2) has been prepared by flash evaporation technique on Corning glass substrates heated at T s = 250 °C and annealed at 450 °C in an argon atmosphere. The properties of the resulting films have been examined by scanning electron microscopy (SEM) and X-ray diffraction. The optical measurements have been carried out in the wavelength range 500–3000 nm. X-ray diffraction revealed that the film was single-phase with chalcopyrite structure and has a preferred orientation along the (1 1 2) plane. The determined lattice parameters were a = 5.75 Å and c = 11.56 Å. SEM micrographs revealed grain sizes ranging from 0.03 μm to 0.04 μm. The thickness of the thin films is around 0.8 μm. The absorption coefficient of this film was above 2.25 × 10 4 cm −1 and the band gap was found to be 1.14 eV. The annealing in Ar did not influence the composition of the layers considerably but improved the crystalline structure quality.