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Article Citation - WoS: 15Citation - Scopus: 17Dielectric Dispersion in Ga2s3< Thin Films(Springer, 2017) Alharbi, S. R.; Qasrawi, A. F.In this work, the structural, compositional, optical, and dielectric properties of Ga2S3 thin films are investigated by means of X-ray diffraction, scanning electron microscopy, energy dispersion X-ray analysis, and ultraviolet-visible light spectrophotometry. The Ga2S3 thin films which exhibited amorphous nature in its as grown form are observed to be generally composed of 40.7 % Ga and 59.3 % S atomic content. The direct allowed transitions optical energy bandgap is found to be 2.96 eV. On the other hand, the modeling of the dielectric spectra in the frequency range of 270-1,000 THz, using the modified Drude-Lorentz model for electron-plasmon interactions revealed the electrons scattering time as 1.8 (fs), the electron bounded plasma frequency as similar to 0.76-0.94 (GHz) and the reduced resonant frequency as 2.20-4.60 x10(15) (Hz) in the range of 270-753 THz. The corresponding drift mobility of electrons to the terahertz oscillating incident electric field is found to be 7.91 (cm (2)/Vs). The values are promising as they nominate the Ga2S3 thin films as effective candidates in thin-film transistor and gas sensing technologies.Article Citation - WoS: 9Citation - Scopus: 9Effect of Ytterbium, Gold and Aluminum Transparent Metallic Substrates on the Performance of the Ga2s3< Thin Film Devices(Elsevier Science Bv, 2017) Alharbi, S. R.; Qasrawi, A. F.In the current work, the structural, optical, dielectric and electrical properties of the Ga2S3 thin films which are deposited onto transparent thin Al, Yb and Au metal substrates are characterized by means of transmittance electron microscopy, X-ray diffraction, ultraviolet visible light spectroscopy and impedance spectroscopy techniques. The effects of the metallic substrates on the crystalline nature, energy band gap and dielectric spectra are also investigated. The modeling of the dielectric spectra allowed determining the effect of the Al, Yb and Au thin layers on the electron scattering time, the plasmon frequency, free electron density and drift mobility. In addition, a Yb/Ga2S3/Au Schottky barrier and All Ga2S3/Au back to back Schottky barrier devices (metal-semiconductor-metal (MSM) device) are fabricated and characterized by means of capacitance-voltage characteristics and capacitance and conductance spectra in the frequency range of 10-1800 MHz. While the Schottky barrier device displayed three distinct positions of resonance-antiresonance phenomena, the MSM device displayed one peak with narrow bandwidth of 10 MHz. The MSM devices exhibited an inversion, depletion and accumulation modes within a voltage range of 0.25 V width at 250 MHz. The study indicates the applicability of these device as smart capacitive switches, as Plasmon devices and as wavetraps. (C) 2017 Elsevier B.V. All rights reserved.Article Citation - WoS: 18Citation - Scopus: 21Engineering the Optical and Dielectric Properties of the Ga2s3< Nanosandwiches Via Indium Layer Thickness(Springer, 2018) Nazzal, Eman O.; Qasrawi, A. F.; Alharbi, S. R.In this study, the effect of the nanosandwiched indium slab thickness (20-200 nm) on the performance of the Ga2S3/In/Ga2S3 interfaces is explored by means of X-ray diffraction, Raman spectroscopy, and optical spectroscopy techniques. The indium slab thickness which was varied in the range of 20-200 nm is observed to enhance the visible light absorbability of the Ga2S3 by 54.6 times, engineered the energy band gap in the range of 3.7-1.4 eV and increases the dielectric constant without, significantly, altering the structure of the Ga2S3. The broad range of the band gap tunability and the increased absorbability nominate the Ga2S3 thin films for photovoltaic applications. In addition, the dielectric spectral analysis and modeling have shown that a wide variety in the plasmon resonant frequency could be established within the Ga2S3/In/Ga2S3 trilayers. The plasmon frequency engineering in the range of 0.56-2.08 GHz which is associated with drift mobility of 12.58-5.76 cm(2)/Vs and electron scattering time at femtosecond level are promising for the production of broad band high frequency microwave filters.Article Citation - WoS: 9Citation - Scopus: 8Plasmon Interactions at the (ag, Al)/Inse Thin-Film Interfaces Designed for Dual Terahertz/Gigahertz Applications(Springer, 2017) Al Garni, S. E.; Omar, A.; Qasrawi, A. F.In this article, we investigate the plasmon-dielectric spectral interaction in the Ag/InSe and Al/InSe thin-film interfaces. The mechanism is explored by means of optical absorbance and reflectance at terahertz frequencies and by the impedance spectroscopy at gigahertz frequencies. It was observed that the interfacing of the InSe with Ag and Al metals with a film thickness of 250 nm causes an energy band gap shift that suits the production of thin-film optoelectronic devices. The reflectance and dielectric constant and optical conductivity spectral analysis of these devices displayed the properties of wireless band stop filters at 390 THz. The physical parameters which are computed from the conductivity spectra revealed higher mobility of charge carriers at the Al/InSe interface over that of Ag/InSe. The respective electron-bounded plasmon frequencies are found to be 2.61 and 2.13 GHz. On the other hand, the impedance spectral analysis displayed a microwave resonator feature with series resonance peak position at 1.68 GHz for the Al/InSe/Ag interface. In addition, the temperature-dependent impedance spectra, which were recorded in the temperature range of 300-420 K, revealed no significant effect of temperature on the wave trapping properties of the Al/InSe/Ag interface. The sensitivity of the interfaces to terahertz and gigahertz frequencies nominates it as laser light/microwave traps, which are used in fibers and communications.
