Yazar "Hamarsheh, Areen A." seçeneğine göre listele

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    Au/CdBr2/SiO2/Au Straddling-Type heterojunctions designed as microwave multiband pass filters, negative capacitance transistors and current rectifiers
    (Wiley, 2021) Qasrawi, Atef Fayez; Hamarsheh, Areen A.
    Herein, nanosheets of SiO2 of thicknesses of 25-100 nm are employed to enhance the performance of Au/CdBr2 Schottky barriers. The Au/CdBr2/SiO2/Au straddling type heterojunction devices is prepared by the thermal evaporation technique. It is observed that SiO2 layers enhances the crystallinity of CdBr2 through increasing the crystallite sizes and decreasing the defect density, stacking faults and microstrain by 50%, 56%, 32% and 34%, respectively. A work function of 6.38 eV is determined from the temperature dependent electrical resistivity measurements of p?type CdBr2. In addition, it was observed that, when coated with 50 nm thick SiO2, the Au/CdBr2/SiO2/Au straddling type transistors can reveal high current rectification ratios of 6.9× 102 at low biasing voltages in the range of 0.06-0.30 V. The alternating current signals analysis in the microwave range of spectra indicated that the current conduction mechanism is dominated by the correlated barrier hopping and quantum mechanical tunneling. It was observed that the Au/CdBr2/SiO2/Au devices exhibit negative effect accompanied with resonance-antiresonance in the capacitance spectra. Moreover, the microwave cutoff frequency which reaches ~165.1 GHz and the magnitude of reflection coefficient spectra has shown that the device under study can perform as multiband pass/stop filters suitable for wire/wireless communication applications including 3G/4G technologies.
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    Band offsets, electron affinities and optical dynamics at the CdBr2/SiO2 interfaces
    (Elsevier, 2021) Qasrawi, Atef Fayez; Hamarsheh, Areen A.
    Indexed keywords Funding details Abstract Herein, the structural, optical, dielectric and optical conductivity parameters of the CdBr2/SiO2 interfaces are reported. Thin films of CdBr2 are coated with 50 nm thick SiO2 under a vacuum pressure of 10?5 mbar. The structural morphological and optical investigations have shown that CdBr2 exhibit hexagonal structure of lattice parameters of a=b=7.20Å and =13.86 Å, energy band gap of 3.32 eV and Urbach energy of 0.84 eV. The interfacing of CdBr2 films with SiO2, shortened the lattice parameters, blue-shifted the energy band gap and decreased the Urbach energy value. The electron affinity of CdBr2 which is determined here is found to be 3.27 eV. The CdBr2/SiO2 interfaces displayed a conduction and a valence band offsets of 2.37 eV and 3.21 eV, respectively. In addition, the dielectric dispersion and optical conduction analyses using the Drude-Lorentz approach have shown that the drift mobility and plasmon frequency (Wpi) of the free charge carriers at the CdBr2/SiO2 interfaces varies in the range of 28.59–22.87 cm2/Vs and 0.41–6.47 GHz, respectively. The effectiveness of the plasmon frequency to limit signal propagation in the heterojunction devices is confirmed by the impedance spectroscopy technique which showed radiowave (RF) band filter characteristics at the targeted Wpi. The energy band offsets, the optical conductivity parameters and the RF filtering properties nominates the CdBr2/SiO2 heterojunctions for use in thin film transistor technology.
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    Design of Au/Cdbr2/Au as negative capacitance devices and as band filters suitable for 4G technologies
    (SciELO, 2021) Qasrawi, Atef Fayez; Hamarsheh, Areen A.
    Herein, cadmium bromide thin film devices are designed for possible use in communication technology. The 1.0 thin layer of CdBr2 is sandwiched between two Au (1.0 thick) layers using the thermal evaporation technique under a vacuum pressure of 10-5 mbar. The Au/CdBr2/Au devices are structurally morphologically and electrically characterized. It is observed that the hexagonal cadmium bromide exhibits large lattice mismatches with cubic Au substrates. The randomly distributed nano- rod like grains is accompanied with average surface roughness of ~26 nm. When an ac signal of low amplitude is imposed between the terminals of the Au/CdBr2/Au devices, a negative capacitance effect in the frequency domain of 10-1800 MHz is observed. In addition, analysis of the impedance spectra in the same domain has shown that the device behaves as band pass/stop filters suitable for 4G technology. The microwave based standard analysis of the Au/CdBr2/Au band filters have shown that it displays a notch () frequency of 2.0 GHz. The cutoff frequency at reaches 7.86 GHz. The features of the Au/CdBr2/Au devices nominate it for use as microwave resonators and as negative capacitance devices suitable for; 4G technology, noise reduction and for parasitic capacitance cancellation.