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Article Citation - WoS: 11Citation - Scopus: 12Effect of Au Nanosandwiching on the Structural, Optical and Dielectric Properties of the as Grown and Annealed Inse Thin Films(Elsevier Science Bv, 2017) Omareya, Olfat A.; Qasrawi, A. F.; Al Garni, S. E.In the current work, the structural, optical and dielectric properties of the InSe/Au/InSe nanosandwiched structures are investigated by means of X-ray diffraction and UV-visible light spectrophotometry techniques. The insertion of a 20 and 100 nm thick Au metal slabs between two InSe layers did not alter the amorphous nature of the as grown InSe films but decreased the energy band gap and the free carrier density. It also increased; the absorption ratio and the values of dielectric constant by similar to 3 times. The insertion of 100 nm Au layers as a nanosandwich enhanced the drift mobility (31.3 cm(2)/V s) and plasmon frequency (1.53 GHz) of the InSe films. On the other hand, upon annealing, a metal induced crystallization process is observed for the InSe/Au (100 nm)/InSe sandwiches. Particularly, while the samples sandwiched with a layer of 20 nm thickness hardly revealed hexagonal gamma -In2Se3 when annealed at 300 degrees C, those sandwiched with 100 nm Au slab, displayed well crystalline phase of hexagonal gamma -In2Se3 at annealing temperature of 200 degrees C. The further annealing at 300 degrees C, forced the appearing of the orthorhombic In4Se3 phase. Optically, the annealing of the InSe/Au(100 nm)/InSe at 200 degrees C improved the absorption ratio by similar to 9 times and decreased the energy band gap. The nanosandwiching technique of InSe seems to be promising for the engineering of the optical properties of the InSe photovoltaic material.Article Citation - WoS: 11Citation - Scopus: 11Formation and Characterization of Cd2s3< Polycrystalline Films Onto Glass and Lanthanum Substrates(Springer, 2019) Qasrawi, A. F.; Omareya, Olfat A.In this article, the structural, optical and dielectric properties of the rarely investigated Cd2S3 thin films are reported. Particularly, Cd2S3 thin films prepared by the thermal evaporation technique onto glass, and 150-nm-thick lanthanum transparent substrate studied by means of energy-dispersive structural analysis have shown that the Cd2S3 thin films are of polycrystalline nature. The hexagonal unit cell parameters, which slightly differ from that of CdS, increased upon replacement of glass with lanthanum. All the other structural parameters including the grain size, strain and defect density are accordingly affected. While the optical band gap increased when La replaces glass, the high-frequency dielectric constant decreased. On the other hand, the Drude-Lorentz modeling of the dielectric spectra has shown that the La/Cd2S3 thin films are promising materials for production of thin film transistors as they exhibit drift mobility values of approximate to 13.3cm(2)/Vs. The response of the glass/Cd2S3 and La/Cd2S3 interfaces to the incident electromagnetic light is associated with hole-plasmon interactions that are limited by plasmon frequency values in the range of 0.4-8.1GHz. Such property makes this material attractive as microwave band pass/reject filters.
