Tin Selenide (SnSe) thin films were prepared from the pulverized compound material by thermal evaporation method, to study the effect of film thickness on its structural, and optical properties. The different thicknesses of SnSe thin films, from 150 nm to 500 nm, were grown on glass substrate held at room temperature. X-ray diffraction, atomic force microscopy, transmission measurement, and four-point probe method were used to characterize the thin films. The optical transmission spectra suggests, the energy band gap decreases with increasing the film thickness. The electrical resistivity shows that the films were semi-conducting in behavior having p-type conductivity.

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Facile synthesis is demonstrated formation of CuO/rGO composite for enhanced optical and electrical characteristics for sensing and photonic devices. CuO nanoparticles synthesized using sol-gel method and various rGO percentages (10-30%) were loaded to form composite via ultra-sonic assisted technique. Structural study using X-ray diffraction and transmission electron microscopy confirms formation of CuO polyhedral nanoparticles with monoclinic structure showing deviations in unit cell parameters, crystallite size, and axis strain. These deviations cause transformation of polyhedral particles into rod-shaped nanocomposites with embedded CuO single crystals with changed rGO. X-ray photoelectron spectroscopy showed varied elemental composition of CuO/rGO nanocomposites with Cu2+ chemical state. Optical measurements exhibit modified direct (1.54-1.51 eV) and indirect bandgap (1.38-1.31 eV) having higher absorption in visible to near infrared (NIR) region for photovoltaic applications. Raman spectroscopy and Fourier transform infrared spectroscopy confirms the presence of Raman active bands and functional groups corresponding to Cu-O. Electrical measurements show decreased resistance with increased rGO incorporation. The higher presence of oxygen sites and low resistance facilitate easy electron transport along with an optimum bandgap (1.51 eV) and higher absorption in visible to NIR region showed possible utility of the grown nanoparticles and composites in gas/photo sensing and optoelectronic applications.

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