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Article Citation - WoS: 7Citation - Scopus: 7Design of the Zns/Ge pn Interfaces as Plasmonic, Photovoltaic and Microwave Band Stop Filters(Elsevier Science Bv, 2017) Alharbi, S. R.; Qasrawi, A. F.In the current work, we report and discuss the features of the design of a ZnS (300 nm)/Ge (300 nm)/GaSe (300 nm) thin film device. The device is characterized by the X-ray diffraction, electron microscopy, energy dispersive X-ray spectroscopy (EDS), optical spectroscopy, microwave power spectroscopy and light power dependent photoconductivity. While the X-ray diffraction technique revealed a polycrystalline ZnS coated with two amorphous layers of Ge and GaSe, the hot probe tests revealed the formation of pn interface. The optical spectra which were employed to reveal the conduction and valence band offsets at the ZnS/Ge and Ge/GaSe interface indicated information about the dielectric dispersion at the interface. The dielectric spectra of the ZnS/Ge/GaSe heterojunction which was modeled assuming the domination of surface plasmon interactions through the films revealed a pronounced increase in the drift mobility of free carriers in the three layers compared to the single and double layers. In the scope of the fitting parameters, a wave trap that exhibit filtering properties at notch frequency of 2.30 GHz was designed and tested. The ac signals power spectrum absorption reached similar to 99%. In addition, the photocurrent analysis on the ZnS/Ge/GaSe interface has shown it is suitability for photovoltaic and photosensing applications. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND licenseArticle Citation - WoS: 11Citation - Scopus: 11Optical and Electrical Performance of Yb/Inse Interface(Elsevier Sci Ltd, 2016) Alharbi, S. R.; Qasrawi, A. F.In this study a 300 nm ytterbium transparent thin film is used as substrate to a 300 nm thick InSe thin film. The optical transmittance, reflectance and absorbance of the glass/InSe and Yb/InSe films are measured and analyzed. The optical data allowed determining the effects of the Yb layer on the energy band gap, on the dielectric and on optical conductivity spectra. The band gap of the InSe films shrunk from 2.38/139 to 1.90/1.12 eV upon Yb layer interfacing leading to a band offset of 0.48/0.27 eV. On the other hand, the modeling of the optical conductivity in accordance with the Lorentz theory revealed a free carrier scattering time, carrier density and mobility of 0.225 (fs), 3.0 x 10(19)(cm(-3)) and 2.53 cm(2)/Vs for the Yb/InSe interface, respectively. As these values seem to be promising for employing the Yb/InSe interface in thin film transistor technology, the current voltage characteristics of Yb/InSe/C Schottky diode were recorded and analyzed. The electrical analysis revealed the removal of the tunneling channels by using Yb in place of Al. In addition, the "on/off' current ratios, the Schottky barrier height and the switching voltage of the Yb/InSe/C device are found to be 18.8, 0.76/0.60 eV and 0.53 V, respectively. (C) 2015 Elsevier Ltd. All rights reserved.Article Citation - WoS: 9Citation - Scopus: 9Optical Dynamics in the Ag/Α-ga2< Layer System(Elsevier Sci Ltd, 2018) Alharbi, S. R.; Qasrawi, A. F.In this work, thin films of Ga2S3 are deposited onto 150 nm thick transparent Ag substrate by the physical vapor deposition technique under vacuum pressure of 10(-5) mbar. The films are studied by the X-ray diffraction and optical spectrophotometry techniques. It is found that the Ag substrate induced the formation of the monoclinic alpha-Ga2S3 polycrystals. The transparent Ag substrate also changed the preferred optical transition in Ga2S3 from direct to indirect It also increased the light absorption by 79 and 23 times at incident light energies of 2.01 and 2.48 eV, respectively. In addition, a red shift in all types of optical transitions is observed. Some the extended energy band tails of Ag appears to form interbands in the band gap of Ga2S3. These interbands strongly attenuated the dielectric and optical conduction parameters. Particularly, an enhancement in the dielectric constant values and response to incident electromagnetic field is observed. The Drude-Lorentz modeling of this interface has shown that the free carrier density, drift mobility, plasmon frequency and reduced electron-plasmon frequency in Ga2S3 increases when the Ag substrate replaced the glass or other metals like Yb, Al and Au. The nonlinear optical dynamics of the Ag/Ga2S3 are promising as they indicate the applicability of this interface for optoelectronic applications.
