STRUCTURAL AND OPTICAL-PROPERTIES OF IN4SE3 THIN-FILMS OBTAINED BY FLASH EVAPORATION

Structural identification shows that the important thin films of composition In4Se3 can be obtained by the flash evaporation technique from a critical ratio of metal/calgonite of 1.247 in the material from which the films are prepared. At a substrate temperature of 450 K, the thin films are polycrystalline. The structural characterization by X-ray diffraction shows that the films are orthorhombic with a texture in which the b-axis is parallel to the substrate. The IR studies of the films confirm the results obtained by the X-ray diffraction. The spectral absorption study in the range of 0.8-1.8 eV indicates a direct optical gap at 1.24 eV. Calculations show that the allowed indirect transitions are not negligible and are contributed to the absorption spectra, the indirect gap is found to be at 1.17 eV.