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Article Citation - WoS: 7Citation - Scopus: 7Enhancements of Light Absorbability, Optical Conductivity, and Terahertz Cutoff Frequency in Stacked Layers of Selenium Via Ag Nanoslabs Sandwiching(Wiley-v C H verlag Gmbh, 2019) Qasrawi, Atef F.; Abu Al Rob, Osama H.Herein, the effects of insertion of Ag layer of thickness of 100 nm between two stacked layers of selenium are investigated by means of X-ray diffraction, scanning electron microscopy, and optical spectrophotometry techniques. While the structural analysis shows the amorphous nature of growth of the stacked layers of Se, the morphology analysis shows the formation of nanorods and nanowires that exhibit lengths and diameters in the ranges of 1.5-2.5 mu m and 36-146 nm, respectively. The optical spectroscopy analysis shows that the presence of Ag between stacked layers of selenium enhances the light absorbability, increases the optical conductivity, and widens the range of the terahertz cutoff frequency. In addition, Ag layers increase the drift mobility from 15.07 to 35.64 cm(2) Vs(-1) and extend the plasmon frequency domain of stacked layers of selenium from 0.45-5.60 to 0.62-5.90 GHz. The calculated optical conductivity parameters and the spectral analysis of the terahertz cutoff frequency that vary in the range of 0.35-13.20 THz indicate the applicability of the Ag sandwiched selenium stacked layers as terahertz cavities suitable for visible-light communications as band-pass filters.Article Citation - WoS: 8Citation - Scopus: 8Optical Interactions in the Inse/Cdse Interface(Wiley-v C H verlag Gmbh, 2016) Qasrawi, A. F.; Rabbaa, S.In this work, the structural and optical properties of the InSe/CdSe heterojunction are investigated by means of X-ray diffraction and ultraviolet-visible light spectrophotometry techniques. The hexagonal CdSe films that were deposited onto amorphous InSe and onto glass substrates at a vacuum pressure of 10(-5)mbar, exhibited interesting optical characteristics. Namely, the absorption, transmission, and reflection spectra that were recorded in the incident light wavelength range of 300-1100nm, for the InSe, CdSe, and InSe/CdSe interface revealed direct allowed transition energy bandgaps of 1.44, 1.85, and 1.52eV, respectively. The valence-band offset for the interface is found to be 0.36eV. On the other hand, the dielectric constant spectral analysis displayed a large increase in the real part of the dielectric constant associated with decreasing frequency below 500THz. In addition, the optical conductivity spectra that were analyzed and modeled in accordance with the Drude theory displayed a free-carrier average scattering time of 0.4fs and a drift mobility of 6.65cm(2)V(-1)s(-1) for the InSe/CdSe interface. The features of this interface nominate it as a promising member for the production of optoelectronic Schottky channels and as thin-film transistors.Article Citation - WoS: 10Citation - Scopus: 9Structural and Optoelectronic Properties of Moo3 Interfaces(Wiley-v C H verlag Gmbh, 2019) Alharbi, Seham Reef; Qasrawi, Atef FayezIn this article, the authors discuss the growth nature, the structural, optical and dielectric properties of CuSe thin films deposited onto MoO3 substrate. The films are studied by the X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and ultraviolet-visible light spectroscopy techniques. CuSe thin films are observed to exhibit strained nature of growth when grown onto MoO3 amorphous substrates. Optically, the MoO3/CuSe films are found to exhibit conduction (Delta Ec) and valence (Delta Ev) band offsets of values of 3.70 and 3.42 eV, respectively. In addition, a remarkable increase in the absorbability (R lambda) of MoO3 by 72 times at 3.0 eV is obtained as a result of coating it with CuSe. The Delta Ec, Delta Ev, and R lambda values are significantly high and nominate the MoO3/CuSe interfaces for use in many optoelectronic applications. In addition, the dielectric analysis shows that the MoO3/CuSe heterojunction exhibit optical conductivity parameters that make it suitable for use in optical communications. Particularly, the Drude-Lorentz modeling of the imaginary part of the dielectric constant for the MoO3/CuSe interfaces displays mobility and plasmon frequency values of 7.76 cm(2) V-1 s(-1) and 3.78 GHz, respectively. The obtained plasmon frequency values indicate the applicability of this device in microwave technology.
