Characterization of stepwise flash evaporated CuIn3Se5 films

CuIn3Se5 thin films were grown by stepwise flash evaporation from the polycrystalline powder source. Bulk CuIn3Se5 was synthesized by melt-quench technique, starting from the stoichiometric mixture of constituent elements. Phase purity of the synthesized material was confirmed by powder X-ray diffraction. Structural investigations by transmission electron microscopy (TEM) show that the films grown at 370 K and above were polycrystalline in nature. Compositional analysis by Rutherford backscattering spectrometry (RBS) revealed that the films have near stoichiometric composition. Analysis of optical transmittance data yielded a band gap value of ∼1.26±0.02 eV.