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Article Citation - WoS: 3Citation - Scopus: 3Current Transport Mechanism in Au-p-mgo-ni Schottky Device Designed for Microwave Sensing(Natl inst Optoelectronics, 2016) Qasrawi, A. F.; Khanfar, H. K.; Department of Electrical & Electronics EngineeringAu/MgO/Ni back to back Schottky tunnelling barriers are designed on the surface of an MgO thin layer and are electrically characterized. The current voltage curve analysis has shown that thermionic emission, field effect thermionic (FET) emission and space charge limited current are dominant transport mechanism in distinct biasing regions. It was shown that, while the device is reverse biased with voltages less than 0.31 V, it conducts by tunnelling (FED though an energy barrier of 0.88 eV with a depletion region width of 15.7 nm. As the voltage exceeds 0.46 V, the tunnelling energy barrier is lowered to 0.76 eV and the depletion region widens and arrives at the reach-through running mode. The device was tested in the microwave electromagnetic power range that extends from Bluetooth to WLAN radiation levels at oscillating frequencies of 0.5 and 2.9 GHz. In addition, a low power resonating signal that suits mobile data is superimposed in the device. It was observed that the Au/MgO/Au sensors exhibit a wide tunability range via voltage biasing or via frequency control. The signal quality factor is 3.53 x 10(3) at 2.9 GHz. These properties reflect applicability in microwave technology as wireless and connectorized microwave amplifiers, microwave resonators and mixers.Article Citation - WoS: 2Citation - Scopus: 2Effects of Laser Excitation and Temperature on Ag/Gase0.5< Microwave Filters(Springer, 2014) Qasrawi, A. F.; Khanfar, H. K.The effects of temperature, illumination, and microwave signals on Ag/GaS0.5S0.5/C Schottky-type microwave filters have been investigated. The devices, which were produced from thin layers of GaSe0.5S0.5 single crystal, had room temperature barrier height and ideality factor of 0.65 eV and 3.28, respectively. Barrier height increased uniformly with increasing temperature, at 2.12 x 10(-2) eV/K, and the ideality factor approached ideality. The devices can even function at 95A degrees C. A current switching phenomenon from low to high injection ("On/Off") was also observed; this current switching appears at a particular voltage, V (s), that shifts toward lower values as the temperature is increased. When the devices were reverse-biased and illuminated with a laser beam of wavelength 406 nm, a readily distinguishable V (s) was observed that shifted with increasing laser power. When the devices were run in passive mode and excited with an ac signal of power 0.0-20.0 dBm and frequency 0.05-3.0 GHz they behaved as band filters that reject signals at 1.69 GHz. Device resistance was more sensitive to signal amplitude at low frequencies (50 MHz) than at high frequencies. The features of these Ag/GaS0.5S0.5/C Schottky devices imply that they may be used as optical switches, as self standing, low band-pass, band reject filters, and as high band-pass microwave filters.
