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Article Citation - WoS: 8Citation - Scopus: 8Design and performance of Yb/ZnS/C Schottky barriers(Elsevier Science Bv, 2017) Khusayfan, Najla M.; Al Garni, S. E.; Qasrawi, A. F.In this work, ZnS thin films are deposited onto glass and transparent ytterbium substrates under vacuum pressure of 10(-5) mbar. The effects of the Yb substrate on the structural, mechanical, optical, dielectric and electrical performance of the ZnS are explored by means of the energy dispersion X-ray analyzer, X-ray diffraction, UVeVIS spectroscopy, current-voltage characteristics and impedance spectroscopy techniques. The techniques allowed determining the lattice parameters, the grain size, the degree of orientation, the microstrain, the dislocation density, the optical and the excitonic gaps, the energy band offsets and the dielectric resonance and dispersion. The (111) oriented planes of glass/ZnS and Yb/ZnS exhibited 2.06% lattice mismatch between Yb and ZnS and degree of orientation values of 63% and 51.6%, respectively. The interfacing of the ZnS with Yb shrunk the energy band gap of ZnS by 0.50 eV. On the other hand, the electrical analysis on the Yb/ZnS/C Schottky device has revealed a rectification ratio of 3.48 x 10(4) at a biasing voltage of 0.30 V. The barrier height and ideality factor was also determined. Moreover, the impedance spectroscopy analysis have shown that the Yb/ZnS/C device is very attractive for use as varactor devices of wide tunability. The device could also be employed as microwave resonator above 1337 MHz. (C) 2016 Elsevier B. V. All rights reserved.Article Citation - WoS: 12Citation - Scopus: 13Performance of the Au/Mgo Photovoltaic Devices(Elsevier Sci Ltd, 2015) Khanfar, H. K.; Qasrawi, A. F.A 100 mu m thick MgO film is used to design a metal semiconductor metal device. The device is characterized by means of current voltage characteristics in the dark and under various light energies in the photon energy range of 3.70-2.15 eV. A photovoltaic effect presented by an open circuit voltage of 0.12-0.47 V. short circuit current density of 3.9-10.5 mu A/cm(2), quantum efficiency of 0.662-0.052, and responsivity of 0.179-0.024 A/W under photoexcitation optical power of 2.2-28.2 mu W is observed. The device was also tested as a UV optical communication component. The test revealed a wide range of tunability and sensitivity for microwave resonant frequencies of 0.5 and 2.9 GHz. The differential resistance of the device exhibited different values at each applied ac signal frequency. When the frequency is fixed, the illuminated to the dark current ratio remained constant for all signal powers in the range of 0.00-20.0 dBm. (C) 2014 Elsevier Ltd. All rights reserved.Article Citation - WoS: 12Citation - Scopus: 14Engineering the Structural, Optical and Dielectric Properties of Znse Thin Films Via Aluminum Nanosandwiching(Elsevier Gmbh, 2019) Qasrawi, A. F.; Alsabe, Ansam M.In this work, two stacked layers of ZnSe thin films are nanosandwiched with aluminum slabs of variable thickness in the range of 10-100 nm. The films which are studied by the X-ray diffraction and ultra-violet visible light spectroscopy techniques exhibit interesting features presented by extension of the cubic lattice parameter, increase in the grain size and reduction in both of the microstrains and defect density. The Al nanosandwiching successfully engineered the energy band gap through narrowing it from 2.84 to 1.85 eV. In addition, the Al nanosandwiching is observed to form interbands that widens upon increasing the Al layer thickness. It also changed the electronic transition nature from direct allowed to direct forbidden type. Moreover, remarkable enhancement in the light absorbability by 796 times is observed near 1.72 eV for two stacked ZnSe layers nanosandwiched with Al slab of thickness of 100 nm. The dielectric constant is also increased three times and the dielectric tenability vary in the range of 3.0-1.2 eV. The nonlinearity in the dielectric spectra and the engineering of the band gap that become more pronounced in the presence of Al slabs make the ZnSe more attractive for nonlinear optical applications.
