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Article Citation - WoS: 11Citation - Scopus: 11Band Offsets, Optical Conduction, and Microwave Band Filtering Characteristics of Γ-in2se3< Heterojunctions(Wiley-v C H verlag Gmbh, 2020) Qasrawi, Atef F.; Kmail, Reham R.Herein, the design and experimental characterization of gamma-In2Se3/CuO interfaces are considered. Thin films of gamma-In(2)Se(3)are coated with thin layers of CuO at room temperature. The heterojunction device is structurally, morphologically, and optically characterized. It is observed that the coating of CuO onto gamma-In(2)Se(3)engenders the formation of CuSe(2)at the ultrathin interface. The gamma-In2Se3/CuO heterojunctions exhibit maximum possible conduction and valence band offsets of values 0.47 and 0.96 eV, respectively. The dielectric spectra display two dielectric resonance peaks at 2.96 and 1.78 eV. In addition, analyses of the optical conductivity spectra reveal accurate drift mobility and plasmon frequency values of 31.31 cm(2) Vs(-1)and 1.5 GHz, respectively. The ability of the device to control the signal propagation at gigahertz level is experimentally tested by the impedance spectroscopy technique which proved the ability of the device to behave as bandpass filters of notch frequency of 1.49 GHz. The gamma-In2Se3/CuO heterojunction devices are also observed to display terahertz cutoff frequency values of approximate to 24 THz in the infrared (IR) range of incident photon energy and approximate to 193 THz in the ultraviolet light range. The nonlinear optical performance of the device nominates it for use as terahertz/gigahertz band filters.Article Citation - WoS: 8Citation - Scopus: 10Thickness Effects on the Dielectric Dispersion and Optical Conductivity Parameters of Cuo Thin Films(Wiley, 2020) Qasrawi, Atef F.; Qasrawı, Atef Fayez Hasan; Hamamdah, Alaa A.; Qasrawı, Atef Fayez Hasan; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics EngineeringIn this article, the effect of film thickness on the structural, optical, dielectric, and optical conductivity parameters of CuO thin films are reported. CuO thin films which are prepared by the physical vapor deposition technique under vacuum pressure of 10(-5) mbar with various thicknesses in the range of 50 to 1000 nm are observed to exhibit amorphous nature of growth. The values of the energy bands gaps, the spectral response of the dielectric constant and of the optical conductivity parameters are highly sensitive to the film thickness. Particularly, while the 50 nm thick CuO films exhibits quantum confinement which forces the material to have wide band gap (2.70 eV), the thicker films display an energy band gap in the infrared range of spectrum. It was also observed that the thicker the films, the more pronounced the nonlinear dielectric response. In addition, analysis of the optical conductivity parameters using Drude-Lorentz approach for optical conduction has shown that the 50 nm thick films can display drift mobility value of 4.65 cm(2)/Vs accompanied with plasmon frequency of 1.20 GHz and free carrier density of 7.5x10(17) cm(3). The Drude-Lorentz analysis has also shown that the free carrier density and the plasmon frequency of CuO decreases with increasing film thickness. This decrement is accompanied with enhancement in the drift mobility values which reaches 12.56 cm(2)/V s as the film thickness exceeds 250 nm. Such features of the thin layer of CuO make them suitable for the production of nano/microthin film transistors.Article Citation - WoS: 2Citation - Scopus: 2Post Annealing Effects on the Structural and Optical Properties of Moo3 Sandwiched With Indium Slabs(Iop Publishing Ltd, 2019) Qasrawi, A. F.; Qasrawı, Atef Fayez Hasan; Kmail, Haifaa K.; AbuSaa, M.; Khanfar, Hazem K.; Qasrawı, Atef Fayez Hasan; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics EngineeringMolybdenum trioxide thin films are prepared by the thermal evaporation technique under vacuum pressure of 10(-5) mbar through insertion of indium slabs of thickness of 200 nm between layers of MoO3 and annealing the produced films in the air atmosphere at 250 degrees C for one hour. The films are studied by means of x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and optical spectrophotometry techniques. The structure of the films is found to be composed monoclinic MoO3, tetragonal indium and cubic In2O3. The phase percentage of In2O3 in the films increased to 26.3% upon annealing at 250 degrees C. The annealing process increased the microstrain, the defect density, the oxygen atomic content and lowered the crystallites and grains sizes in the films. Optically, two energy band gaps of values of 3.20 and 1.70 eV were detected for the MoO3/In/MoO3 system. In addition, nonlinear dielectric response associated with wide range of tunability in the dielectric constant value, in the optical conductivity and in the terahertz cutoff frequency was observed in the near IR spectral range. The annealing of the samples improved the nonlinearity in these parameters and make MoO3/In/MoO3 system more appropriates for optoelectronic technology applications as terahertz cavities and frequency convertors.Article Citation - WoS: 6Citation - Scopus: 6Dielectric Dispersion at the Mn/Znpc Interfaces(Wiley-v C H verlag Gmbh, 2020) Qasrawi, Atef F.; Zyoud, Hadeel M.Herein, the effects of manganese transparent (150 nm) substrates on the structural, nonlinear optical, and dielectric properties of zinc phthalocyanine are explored. ZnPc thin films are observed to exhibit deformed crystal structure associated with remarkable enhancement in the light absorbability by 21 times at 2.62 eV and by 173 times in the near-infrared (NIR) region of light upon replacement of glass by transparent Mn substrates. The Mn layer also causes a redshift in the energy bandgap, allows generation of free carrier absorption process and increases the dielectric constant by more than 169% in the NIR region. The interaction between the manganese substrates with the organic ZnPc thin layers decreases the free holes density, widens the plasmon frequency range, and improves the drift mobility of holes. The nonlinear dielectric response with the highly improved light absorbability in the NIR range of light nominates the Mn/ZnPc thin films for optoelectronic applications.
