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Article Citation - WoS: 1Citation - Scopus: 1Structural, Optical and Electrical Properties of Ybinse Thin Films(Elsevier Science Sa, 2016) Alharbi, S. R.; Qasrawi, A. F.In this work, the compositional, the structural, the vibrational, the optical and the electrical characterizations of the YbInSe compound are investigated by means of energy dispersion X-ray analysis, scanning electron microscopy and X-ray diffraction, Raman spectroscopy, ultraviolet-visible light spectrophotometry, impedance spectroscopy and temperature dependent electrical conductivity, respectively. The 300 nm thick YbInSe films which were prepared by the co-evaporation of the source materials under a vacuum pressure of 10(-5) mbar, are observed to exhibit nanocrystalline clusters of size of 27 nm regularly distributed among an amorphous structure. The most intensive Raman active lines are observed at 150 and 254 cm(-1). In addition, the optical analysis has shown that the films exhibit a direct forbidden electronic transitions type energy band gap of 1.07 eV. The optical transitions are associated with interband tail states of width of 0.28 eV. Moreover, the real and imaginary parts of dielectric spectra which were analyzed in the frequency range of 270-1000 THz, were analyzed in accordance with the single oscillator and the Lorentz models, respectively. The modeling allowed determining the oscillator and dispersion energies, the terahertz free carrier scattering time, the free holes effective mass, the carrier density, the drift mobility and the reduced resonant frequency for the YbinSe films. In the electronic part of study, the temperature dependent dc electrical conductivity analysis, indicated the domination of the variable range hopping transport mechanism below 335 K, the thermal excitation of charge carriers in the range of 337390 K and the extrinsic-intrinsic transition property at 390 K. The ac conductivity spectra which were recorded in the frequency range of 10-1500 MHz, revealed the domination of the correlated barrier hopping of free carriers between pairs of localized states at the Fermi level. (C) 2016 Elsevier B.V. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 4Structural and Optical Properties of the Zns/Gase Heterojunctions(Iop Publishing Ltd, 2017) Alharbi, S. R.; Abdallaha, Maisam M. A.; Qasrawi, A. F.In the current work, the ZnS/GaSe thin film heterojunction interfaces are experimentally designed and characterized by means of x-ray diffraction, scanning electron microscopy, energy dispersion spectroscopy and optical spectroscopy techniques. The heterojunction is observed to exhibit physical nature of formation with an induced crystallization of GaSe by the ZnS substrate. For this heterojunction, the hot probe technique suggested the formation of a p-ZnS/n-GaSe interface. In addition, the designed energy band diagram of the heterojunction which was actualized with the help of the optical spectrophotometric data analysis revealed a respective conduction and valence band offsets of 0.67 and 0.73 eV. On the other hand, the dielectric dispersion analysis and modeling which was studied in the frequency range of 270-1000 THz, have shown that the interfacing of the ZnS with GaSe strongly affects the properties of ZnS as it reduces the number of free carriers, shifts down the plasmon frequency, increases the charge carrier scattering time and results in higher values of drift mobility at Terahertz frequencies.
