Yazar "Al Garni, Sabah E." seçeneğine göre listele

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    Ag/SeO2/C avalanche type resonant tunneling schottky barriers
    (SciELO - Scientific Electronic Library Online, 2022) Al Garni, Sabah E.; Qasrawi, A. F.; Khusayfana, Najla M.
    Herein, the design and characterization of Ag/SeO2/C avalanche type resonant tunneling devices are reported. Thin pellets of SeO2 nano-powders pressed under hydraulic pressure of 1.0 MPa which is used as the active material are characterized. They showed tetragonal structure refereeing to space group of and lattice parameters of 7.866 ? and 5.336 ? . The current-voltage characteristic curves have shown that SeO2 can perform as active media to produce resonant tunneling diodes when forward biased and as avalanche type diode when reverse biased. The peak to valley current ratios of these diodes reached 18.3. In addition, the impedance spectroscopy measurements have shown that the device works in the low impedance mode when operated in the microwave range of frequency near 1.50 GHz. Negative conductance effect is observed in that frequency domain. The features of the Ag/SeO2/C nominate them for use as signal amplifiers and microwave oscillators.
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    Growth and characterization of vacuum evaporated MgSe thin films
    (Springer, 2023) Almotiri, R. A.; Qasrawi, Atef Fayez; Al Garni, Sabah E.
    Herein, thin flms of magnesium selenide are thermally grown in a vacuum deposition (VD) system onto glass substrates under a vacuum pressure of 10–5 mbar. The flms are structurally, morphologically, compositionally, and optically characterized. It is observed that MgSe thin flms coated by the VD technique are composed of polycrystalline MgSe1.07 (a=5.149 ?, space group Fm3m) and MgSe1.96 (a=6.514 ?, space group P3?a) cubic phases. The flms displayed an average roughness value of 13 nm. They also exhibited a direct energy band gap of 2.54 eV and an indirect band gap of 3.34 eV. In addition, detailed studies of the dielectric properties, optical conductivity, and terahertz cutof frequency spectra showed the ability of MgSe thin flms to perform as a dielectric material. High dielectric constant values are reached in the near-infrared range of light. As optical conductors, the flms displayed one IR, two visible, and two ultraviolet light oscillators showing a maximum plasmon frequency of 8.19 GHz in the UV range. The drift mobility of these oscillators varied in the range of 4.57–9.67 cm2 / Vs. Moreover, the terahertz cutof frequency for these oscillators varied in the range of 11–175 THz proofng the suitability of MgSe flms for terahertz technology issues.