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Article Citation - WoS: 4Citation - Scopus: 4Electrical Conductivity and Capacitance Spectra of Bi1.37sm0.13< Pyrochlore Ceramic in the Range of 0-3 Ghz(World Scientific Publ Co Pte Ltd, 2014) Qasrawi, A. F.; Bzour, Faten M.; Nazzal, Eman O.; Mergen, A.In this work, the electrical properties of samarium-doped bismuth niobium zinc oxide (Sm-doped BZN) pyrochlore ceramics are investigated by means of temperature dependent electrical conductivity and capacitance spectroscopy in the frequency range of 0-3 GHz. It was observed that the novel dielectric Sm-BZN ceramic exhibits a temperature and electric field dependent dielectric breakdown. When measured at 300 K, the breakdown electric field is 1.12 kV/cm and when heated the breakdown temperature is similar to 420 K. The pyrochlore is thermally active above 440K with conductivity activation energy of 1.37 eV. In addition, the room temperature capacitance spectra reflected a resonance-antiresonance switching property at 53MHz when subjected to an AC signal of low power of 5 dBm. Furthermore, when the Sm-BZN ceramics are used as microwave cavity and tested in the frequency range of 1.0-3.0 GHz, the cavity behaves as low pass filter with wide tunability up to a frequency of 1.91 GHz. At this frequency it behaves as a band rejection filter that blocks waves of 1.91 GHz and 2.57 GHz frequencies. These properties of the Sm-doped BZN are promising as they indicate the usability of the ceramics in digital electronic circuits as resonant microwave cavities suitable for the production of low pass/rejection band filters.Article Citation - WoS: 10Citation - Scopus: 14Impedance Spectroscopic Analysis of the Inse/Znse Interface(Ieee-inst Electrical Electronics Engineers inc, 2017) Al Garni, Sabah E.; Qasrawi, Atef F.In this paper, n-InSe/p-ZnSe/n-InSe (npn) thin-film transistors (TFTs) are deposited onto cubic (111)-oriented Ag, Au, and Al thin-film substrates. The properties of the structures are explored by means of X-ray diffraction and impedance spectroscopy in the frequency range of 10-1800 MHz. Although the Ag, Au, and Al substrates are observed to be well aligned with the cubic ZnSe, the electrical properties of these TFT for the np (InSe/ZnSe) and npn interfaces are different. Namely, while the capacitance of the TFT deposited onto the Ag substrate exhibited positive values, the capacitance of the TFT deposited onto Au and Al films is negative in the range of 10-1100 and 800-1800 MHz, respectively. In addition, even though the impedance of the Ag/np/Ag and Ag/npn/Ag heterojunction monotonically decreasedwith the increasing frequency, the impedance of Au/np/Au and Au/npn/Au interfaces exhibited resonance peaks at 1211 and 1148 MHz, respectively. When the wave trap features are read from reflection spectra, it is observed that the Ag/npn/Ag and the Al/np/Ag exhibit lowpass filter properties and the Au/npn/Au behaves as a bandstop filter at a notch frequency of 1176 MHz. These properties nominate the npn transistors for use as microwave traps and as high-speed CMOS amplifiers.Article Citation - WoS: 3Citation - Scopus: 4Au/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.Article Citation - WoS: 4Citation - Scopus: 5Electrical Characterization of Bi1.50-x< Varactors(World Scientific Publ Co Pte Ltd, 2014) Qasrawi, A. F.; Abu Muis, Khalil O.; Abu Al Rob, Osama H.; Mergen, A.The electrical properties of yttrium doped bismuth zinc niobium oxide (BZN) pyrochlore ceramics are explored by means of temperature dependent electrical conductivity dielectric constant and capacitance spectra in the frequency range of 0-3 GHz. It is observed that the doped BZN exhibit a conductivity type conversion from intrinsic to extrinsic as the doping content increased from 0.04 to 0.06. The thermal energy bandgap of the intrinsic type is 3.45 eV. The pyrochlore is observed to exhibit a dielectric breakdown at 395 K. In addition, a negative capacitance (NC) spectrum with main resonance peak position of 23.2 MHz is detected. The NC effect is ascribed to the increased polarization and the availability of more free carriers in the device. When the NC signal amplitude is attenuated in the range of 0-20 dBm at 50 MHz and 150 MHz, wide tunability is monitored. Such characteristics of the Y-doped BZN are attractive for using them to cancel the positive parasitic capacitance of electronic circuits. The canceling of parasitic capacitance improves the high frequency performance of filter inductors and reduces the common mode noise of the resonance signal.Article Citation - WoS: 9Citation - Scopus: 9Yb/Inse Straddling-Type Tunneling Devices Designed as Photosensors, Mos Capacitors, and Gigahertz Bandstop Filters(Ieee-inst Electrical Electronics Engineers inc, 2021) Alfhaid, Latifah Hamad Khalid; Qasrawı, Atef Fayez Hasan; Qasrawi, A. F.; AlGarni, Sabah E.; Qasrawı, Atef Fayez Hasan; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics EngineeringIn this work, amorphous InSe thin films coated with 30-160-nm-thick SiO2 are used as an active material to fabricate multifunctional devices. The n-InSe/p-SiO2 layers that are deposited onto ytterbium substrates are optically and electrically characterized. It was observed that the coating of SiO2 nanosheets onto the surface of InSe enhances the light absorbability in the near-infrared range without remarkable altering of the bandgap. Significant increase in the steady-state photocurrent values accompanied by faster photocurrent responses resulted from the coating of SiO2 nanosheets. Electrically, while the Yb/InSe/Au channels display tunneling Schottky barrier characteristics, the Yb/InSe/SiO2/Au channels show pn junction features. Both channels displayed metal-oxide-semiconductors (MOS) capacitance-voltage characteristics. In addition, the analyses of the current-voltage characteristics have shown that the currents in the Yb/InSe/Au and Yb/InSe/SiO2 (30 nm)/Au channel are dominated by electric field-assisted thermionic emission (tunneling) of charge carriers through barriers of widths of 18/14 and 30/16 nm under reverse-/forward-biasing conditions, respectively. Further increase in the oxide layer thickness lowered the barrier height of the devices. On the other hand, when an ac signal of low amplitude is imposed through the device channels, the conductance, capacitance, and reflection coefficient spectra displayed bandstop filter characteristics near 1.6 GHz. The microwave cutoff frequency spectra show a remarkable increase in the cutoff frequency values as a result of the coating of InSe with SiO2 nanosheets. The features of the device assure its applicability as rectifying diodes, fast photosensors, MOS capacitors, and microwave bandstop filters.
