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Article Citation - WoS: 4Citation - Scopus: 4Characterization of the Ge/Bi2< Interfaces(Univ Fed Sao Carlos, dept Engenharia Materials, 2019) Alharbi, Seham Reef; Qasrawi, Atef FayezIn this article, the properties of the Ge/Bi2O3 interfaces as microwave cavities are reported and discussed. The interface is composed of monoclinic Bi2O3 films grown onto polycrystalline cubic Ge substrate. It is observed that consistent with the theoretical design of the energy band diagram, the experimental current-voltage characteristics of the Yb/Ge/Bi2O3/C hybrid device structure exhibits electronic switching property. In addition, the capacitance, resistance and microwave cutoff frequency spectral analysis in the frequency domain of 0.01-1.50 GHz revealed a frequency dependent tunability of the device. Moreover, while the Yb/Bi2O3/C interface displays negative capacitance effect, the Yb/Ge/Bi2O3/C interfaces are also found to have the ability of altering the resistance up to three orders of magnitude. Such property allowed reaching a cut off frequency up to 116 GHz. The electronic features of the device indicated that the Ge/Bi2O3 interfaces are attractive for production of negative capacitance field effect transistors and band pass/reject filters.Article Citation - WoS: 3Citation - Scopus: 3Hot aluminum substrate induced hexagonal-tetragonal phase transitions in InSe and performance of Al/InSe/Cu2O pn tunneling devices(Wiley, 2020) Qasrawi, Atef Fayez; Kmail, Reham RedaIn the current study, we have considered the induced phase transitions in Al/InSe thin film substrates and employing them for fabrication of InSe/Cu2O tunneling channels. The InSe substrates are observed to prefer the transition from the hexagonal gamma-In(2)Se(3)to the rarely observed tetragonal InSe. The phase transitions are obtained by the thermally assisted diffusion of aluminum, which was already kept at 250 degrees C in a vacuum media of 10(-5)mbar before the compensation of InSe. The tetragonal InSe also induced the crystallization of orthorhombic Cu2O with acceptable level of lattice matching along thea-axis. The Al/InSe/Cu2O/Au heterojunctions, which are electrically analyzed are observed to exhibit rectifying features with the current conduction being dominated by electric fields assisted thermionic emission (tunneling) through a barrier of width of 5.5 to 14.0 nm and barrier height of 0.19 to 0.30 eV. The ac analyses of the capacitance and conductance spectra of this device have shown that it can exhibit high/low capacitance and frequency dependent conductance switching modes at 0.12 GHz in addition to negative capacitance effect in the range of 0.12 to 1.80 GHz. The features of the device are promising as they indicate the suitability of the device for fabrication of field effect transistors, memory devices, and ultrafast switches.
