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Article Citation - WoS: 3Citation - Scopus: 4Effects of Ge Substrate on the Structural and Optical Conductivity Parameters of Bi2o3< Thin Films(Elsevier Gmbh, 2019) Alharbi, S. R.; Qasrawi, A. F.In this article the structural, optical and dielectric properties of a 200 nm thick Bi2O3 thin films which are deposited onto amorphous germanium substrate are reported. Both of the Ge and Bi2O3 thin films are prepared by the thermal evaporation technique under vacuum pressure of 10 s mbar. Bi2O3 thin films are found to prefer the monoclinic nature of structure with larger values of microstrain, dislocation density, stacking faults and smaller grain sizes upon replacement of the glass substrate by germanium. Optically, significant redshift in the energy band gap is observed when the films are grown onto Ge. The Ge/Bi2O3 heterojunctions exhibit a conduction and valence band offsets of value of 0.81 and 1.38 eV, respectively. In addition to the enhancement in the dielectric constant near the IR region, the Drude-Lorentz modeling of the Ge/Bi2O3 heterojunctions has shown remarkable effect of the Ge substrate on the optical conductivity parameters of Bi2O3. Particularly, the drift mobility increased by about one order of magnitude, the free hole density decreased by (similar to)24 times and the plasmon frequency ranges extended from 5.21 to 11.0 GHz to 2.59-12.80 GHz when germanium substrate is used. The optical features of the heterojunction nominate it for visible light communication technology.Article Citation - WoS: 1Citation - Scopus: 1Characterization of the Nanosandwiched Ga2s3< Interfaces as Microwave Filters and Thermally Controlled Electric Switches(Elsevier Gmbh, 2018) Alharbi, S. R.; Nazzal, Eman O.; Qasrawi, A. F.In this work, an indium layer of 50 nm thicknesses is sandwiched between two 500 nm thick Ga2S3 layers. The effect of indium nansandwiching on the composition, structure, morphology, light absorbability, capacitance and reactance spectra, and temperature dependent electrical conductivity of the Ga2S3 films are investigated by means of X-ray diffraction, scanning electron microscopy, energy dispersion X-ray spectroscopy, Raman spectroscopy, visible light spectrophotometry, impedance spectroscopy and current voltage characteristics. While the nansandwiched films are observed to exhibit an amorphous nature of structure with indium content of Owing to the nucleation mechanisms that take place during the film growth, the accumulation of some unit cells in groups to form grains should be a significant reason for the existence of many different sizes of grains in the nanosand-wiched films (Alharbi and Qasrawi, 2016). 0, the Raman spectra displayed three vibrational modes at 127.7,145.0 and 274.3 cm(-1). It was also observed that the indium insertion in the structure of the Ga2S3 shrinks the energy band gap by 0.18 eV. The nanosandwiched films are observed to exhibit a semiconductor metal (SM) transition at 310 K. The SM transition is associated with thermal hysteresis that exhibited a maximum value of 16% at 352 K. This behavior of the nanosandwiched films nominate it for use as thermally controlled electric switches. In addition, the impedance spectral analysis in the range of 10-1800 MHz has shown a capacitance tunability of more than 70%. The measurements of the wave trapping property displayed a bandpass/reject filter characteristics above 1.0 GHz which allow using the Ga2S3/In/Ga2S3 thin films as microwave resonator. (C) 2017 Elsevier GmbH. All rights reserved.
