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Access Right: info:eu-repo/semantics/closedAccessSubject: As2Se3/Ag/As2Se3

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    Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Enhancing the Optoelectronic Performance of As2se3< Thin Films Via Ag Slabs Sandwiching
    (Elsevier Gmbh, 2020) Qasrawi, A. F.; Alharbi, Seham Reef
    In this work, the effects of insertion of Ag slabs of thicknesses of 50, 100 and 200 nm between layers of arsenic selenide are reported. The glassy structured As2Se3 is characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, ultraviolet-visible light spectrophotometry and impedance spectroscopy techniques. While the two stacked layers of As2Se3 exhibited high absorption and energy band gap values that nominate them for optoelectronic applications, the Ag slabs enhanced the light absorbability by 3.98, 5.77, 6.13 times and shrunk the energy band gap by 1.16 %, 7.40 % and 13.8 % for Ag slabs of thicknesses of 50, 100 and 200 nm, respectively. In addition, even though the As2Se3/As2Se3 layers exhibited negative capacitance effect in the frequency domain of 0.01-1.80 GHz, the insertion of Ag slabs removed the negative capacitance effect and forced the capacitance spectra to exhibit resonance at critical frequency of value of 0.23 GHz. The modeling of the capacitance spectra have shown that the geometrical capacitance is increased by one order of magnitude upon Ag slabs insertion. The dynamic capacitance is limited by electrons (holes) plasmonic interaction at the interface between the As2Se3/Ag/As2Se3 layers. Furthermore, the capacitance- voltage characteristics of the As2Se3/Ag/As2Se3 films confirmed the suitability of the devices to exhibit MOS device features. The characteristics of the stacked layers of As2Se3 indicate their multi-functionality as an optical absorbers/receivers and as microwave cavities.
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    Article
    Citation - WoS: 3
    Citation - Scopus: 4
    Au/As2< Schottky Barriers Designed as Multifunctional Devices
    (Ieee-inst Electrical Electronics Engineers inc, 2020) Al Harbi, S. R.; Qasrawi, A. F.
    In this article, Au/As2Se3/Ag/As2Se3/Yb Schottky barriers are formed and characterized. The devices prepared by the thermal evaporation technique under vacuum pressure of 10(-5) mbar are observed to exhibit metal-induced crystallization process when coated onto Au substrates. Electrically, the arsenic selenide-based Schottky devices exhibited typical metal-oxide-semiconductor (MOS) characteristics with a built-in potential of 0.17 eV. The device shows resonance-antiresonance switching, negative capacitance (NC) effect, and high to low conductance switching features in the frequency domain of 10-1800 MHz. In addition, measurement of the impedance, amplitude of reflection coefficient, return loss (L-r), and voltage standing wave ratio (VSWR) spectra in the same domain have shown that the Au/As2Se3/Ag/As2Se3/Yb Schottky barriers display band stop features at 1180 MHz. The L-r and VSWR values at this critical frequency are 29.1 dB and 1.1, respectively. The electrical characterizations of the Au/As2Se3/Ag/As2Se3/Yb MOS devices have confirmed their suitability for use as parasitic capacitance cancellers, noise reducers, and as switching clock with selective switching time scales of switching delay time less than 0.40 ns.