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Article Citation - WoS: 5Citation - Scopus: 5Structural and Electrical Characterizations of the as Grown and Annealed Au/Mοo3< Bandpass Filters(Wiley, 2019) Khanfar, Hazem K.; Qasrawi, Atef; Daraghmeh, Masa; Abusaa, MuayadIn this work, the structural, morphology, and electrical properties of two 500 nm thick molybdenum trioxide layers that are sandwiched with indium slab of thickness of 200 nm (MoO3/In/MoO3 [MIM]) to form a bandpass filter are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and impedance spectroscopy techniques, respectively. The MIM films which coated onto Au thin film substrates by the thermal evaporation technique under vacuum pressure of 10(-5) mbar was post annealed at 250 degrees C in air atmosphere. While the XRD analysis revealed polycrystalline hexagonal lattice structure of the Au/MLM samples, the SEM and EDS analysis displayed grains of sizes of 350 nm and stoichiometric structure of MoO3. Electrically, indium layer which caused n-type conduction with donor level of 299 meV, forced the material to exhibit negative capacitance (NC) effect at high frequencies (above 1.1 GHz). The impedance spectroscopy which was recorded in the frequency domain of 0.01 to 1.80 GHz, also revealed low pass and high pass filters characteristics in the low and high frequency domains, respectively. The annealing of the Au/MIM samples, decreased the crystallite and grain sizes and increased the microstrain, the defect density and the stacking faults. Small amount of excess oxygen and some indium deficiency are observed upon annealing. In addition, the annealing shifted the donor level closer to the bottom of the conduction band and inverted the NC effect from high to low frequency regions. The study indicates the applicability of the Au/MIM/C structures as microwave cavities and parasitic capacitance cancellers in electronic circuits.Article Citation - WoS: 13Citation - Scopus: 13Surface Characterization and Corrosion Resistance of Boron Nitride Coated Titanium Dental Implants(Maik Nauka/interperiodica/springer, 2019) Cakal, G. O.; Gokmenoglu, C.; Kaftanoglu, B.; Ozmeric, N.Surface modifications of dental implants are of vital importance to enhance osseointegration and improve their corrosion resistance. This study characterized the surface properties of boron nitride (BN) coated titanium implants and their corrosion behaviors. Pretreated implant surfaces were coated successfully with BN by RF-magnetron sputtering system. Surface morphology and elemental composition of uncoated and BN-coated implant surfaces were examined by using X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) coupled with energy dispersive X-ray spectrometer (EDS). The corrosion tests were performed by use of artificial saliva. The tri-dimensional topography of the uncoated sandblasted, large-grit, acid-etched (SLA) implant surface showing sponge-like characteristics, revealed characteristic differences at micro level after BN-coating. It had more holes and peaks in addition to the sponge-like characteristics which further improved its surface microroughness. Boron-to-nitrogen ratio of the coated surface was obtained in the range of 0.8-1.6. The BN-coated SLA implant had no weight loss in the corrosion test. However, the surface characteristics of implants before coating had an impact on corrosion behavior of other implant types. The results demonstrated that titanium implants can be coated with BN successfully and this coating improves the surface properties of dental implants.
