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Publisher: Elsevier Science SaSubject: X-ray

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    Article
    Citation - WoS: 12
    Citation - Scopus: 11
    Investigation of the Structural and Optoelectronic Properties of the Se/Ga2< Heterojunctions
    (Elsevier Science Sa, 2018) Qasrawi, A. F.
    In the current study, the structural and optical properties of the Se/Ga2S3 heterojunctions are investigated by means of X-ray diffraction and ultraviolet-visible light spectrophotometry techniques. The optical interface which was prepared by the physical vapor deposition technique, comprises a polycrystalline orthorhombic selenium layer of thickness of 500 nm coated with amorphous layer of 200 nm thick Ga2S3. The top layer is observed to cause yield stress on the Se layer leading to strained type interface. Optically, the evaporation of Ga2S3 onto selenium blue shifted the energy band gap of Se. The conduction and valence band offsets exhibited values of 1.28 and 0.20 eV, respectively. On the other hand, the optical conductivity spectra which were studied and modeled by the Drude-Lorentz approach in the terahertz frequency domain of 275-675 THz revealed enhanced optical conduction parameters. The use of Se as substrate to Ga2S3 enhanced the drift mobility and plasmon frequency of the Ga2S3. The value of the drift mobility reached 64 cm(2)/Vs at plasmon frequency of 2.04 GHz. In addition, the Se/Ga2S3 interface are observed to exhibit high biasing dependent photosensitivity to visible light irradiation. Such properties of this interface nominate it for use in optoelectronics including visible light communications. (C) 2018 Elsevier B.V. All rights reserved.
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    Article
    Citation - WoS: 26
    Citation - Scopus: 26
    Fabrication and Some Physical Properties of Agin5s8< Thin Films
    (Elsevier Science Sa, 2004) Qasrawi, AF; Kayed, TS; Ercan, I
    AgIn5S8 thin films are deposited on glass substrates, kept at 300 K, by thermal evaporation of AgIn5S8 single crystals under the pressure of 10-5 Torr. The X-ray fluorescence analysis revealed that the films have a weight percentage of similar to11.5% Ag, 61.17% In, and 27.33% S which corresponds to 1:5:8 stoichiometric composition. X-ray analysis of the films reveals the polycrystalline nature of the films. The lattice parameter (a) of the films was calculated to be 10.784(5) Angstrom. The dark n-type electrical conductivity of the films was measured in the temperature range of 30-350 K. The conductivity data analysis shows that the thermionic emission of the charge carriers having activation energies of 147 and 224 meV in the temperature ranges of 130-230 and 240-350 K, respectively, are the dominant transport mechanism in the films. The variable range hopping transport mechanism is dominant below 130 K. The room temperature photocurrent-photon energy dependency predicts a band gap of 1.91 eV of the films. The illumination intensity-photocurrent dependency measured in the intensity range of 13-235 W cm(-2) reveals monomolecular recombination (linear) in the films and bimolecular recombination (sublinear) at the film surface corresponding to low and high applied illumination intensities, respectively. The time-dependant photocurrent measured at fixed illumination intensity reveals a response time of 0.85, 2.66 and 10.0 s in the time periods of 0-0.5, 0.5-1.0, and 1.0-10.0 s, respectively. (C) 2004 Elsevier B.V. All rights reserved.