Yazar "Abu Alrub, Shatha N." seçeneğine göre listele

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    Amorphous WO3 thin films designed as gigahertz/terahertz dielectric lenses
    (Springer Link, 2022) Qasrawi, Atef Fayez; Abu Alrub, Shatha N.; Daragme, Rana B.
    Herein, tungsten oxide thin films comprising excess oxygen are treated as optical resonator suitable for gigahertz/terahertz applications. WO3 thin films which are prepared by the thermal evaporation technique under a vacuum pressure of 10? 5 mbar are structurally, compositionally and optically evaluated. The amorphous WO3 films which showed high transparency permit electronic transitions within an indirect allowed energy band gap of 3.05 eV. The band gap comprised energy band tails of width of 190 meV. Four dominant dielectric resonators centered in the infrared (IR), visible (VIS) and ultraviolet (UV) ranges of light are detected. Analysis of the optical conductivity in accordance with the Drude-Lorentz approaches have shown that the drift mobility of free holes in this amorphous layer can be as large as 5.61 cm2/Vs an as low as 1.59 cm2/Vs when exposed to IR and UV light signals, respectively. In addition, the gigahertz/terahertz cutoff frequency (fco) spectra demonstrated fco values in the gigahertz frequency domain when exposed to IR light. Excitations with light signals in the VIS and UV spectral ranges allow fco values that extends from 0.7 to 40.0 THz. The wide range of tunability of the WO3 dielectric resonators nominates them as dielectric lenses suitable for optical communications.
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    Band offsets, dielectric dispersion, optical conduction and impedance spectroscopy analyses of WO3/ Ga2S3 heterojunctions
    (Springer, 2022) Qasrawi, Atef Fayez; Abu Alrub, Shatha N.
    Stacked layers of amorphous WO3 and Ga2S3 are fabricated by the thermal evaporation technique under a vacuum pressure of 10– 5 mbar. The structural, compositional, optical, dielectric and electrical properties of the WO3/ Ga2S3 (WG) heterojunctions are investigated. It is observed that the WG heterojunctions exhibit well-aligned conduction bands. The valance band offsets are 0.58 eV. In addition, as a dielectric resonator, WG interfaces displayed single infrared oscillator, double ultraviolet (UV) oscillators and triple visible light oscillators. The optical conductivity modeling by the Drude–Lorentz approach has shown that for these oscillators the drift mobility of charge carriers is 7.52, 9.40 and 18.80 cm2/ Vs, respectively. The optical conductivity in the ultraviolet range is very high nominating the WG interfaces for UV sensing. On the other hand, the impedance spectroscopy analysis for the Yb/WG/C interfaces revealed the wide tunability of the devices when employed as capacitors and as bandpass filters. The WG interfaces can perform as radiowave/microwave band filters. The microwave