İlgi alanları

• MakaleAçık Erişim2022Scopus SJRQ1/r/bayburt/13267
  High optical response NiO, Pd/NiO and Pd/WO3 hydrogen sensors

  Çoban, Ömer; Tekmen, Süleyman; Gür, Emre; Tüzemen, Sebahattin

  In this study, NiO and WO3 oxide semiconductors were fabricated on glass substrates by RF Magnetron Sputtering technique. Structural and optical characterizations of the semiconductors were performed using XRD, SEM, and optical absorption measurements. NiO and WO3 thin films were occasionally coated with palladium. In order to investigate the optical response of these semiconductors under hydrogen gas exposure, an optical gas sensor test system was installed and programmed. In both of the coated and uncoated cases, optical absorption changes due to hydrogen gas exposure on the surface were investigated. It was observed that these changes occur between 450 and 850 nm wave lengths range. The absorption in the NiO semiconductor was reduced between these wave lengths, while the absorption was increased in the WO3 semiconductor. In the uncoated state, only NiO gave an optical response to hydrogen gas. While the palladium coated NiO (Pd/NiO) sensor had the best response and recovery times of respectively 70 s and 206 s for 2% fraction of H2 gas at 300 °C constant temperature, the Pd/WO3 sensor gave the best response time of 340 s. Palladium coating resulted in approximately 150% increase in the responses of the NiO sensors at higher H2 concentration. The lower limit of H2 sensing of the Pd/NiO sensors at 300 °C was at the H2 fraction of 0.05%, while for Pd/WO3 sensors this value was 0.025%.

  AtıfScopus26·WoS25·OpenAlex26

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• MakaleYayıncıda açık erişim2020Scopus SJRQ1/r/bayburt/13526
  Temperature dependent current- and capacitance-voltage characteristics of W/n-Si structures with two-dimensional WS2 and three-dimensional WO3 interfaces deposited by RF sputtering technique

  Baltakesmez, A.; Tekmen, S.; Güzeldir, B.

  In this study, tungsten disulfide (WS2) and tungsten trioxide (WO3) thin films are deposited on n-Si by RF sputtering technique. The optical, morphological and structural characteristics of these films are investigated. The XRD patterns showed that highly crystallinity have been obtained with dominant characteristic diffraction peaks of the WS2 and WO3. The SEM images show that these films are nearly uniform and covered all surface of substrates. Furthermore, the WS2 film has two-dimensional (2D) vertical layers while the WO3 has three-dimensional (3D) structure. From the XPS spectra, it revealed that the peaks confirmed the formation of WS2 and WO3 phases. The Raman spectra presented that different vibrational modes and phases are characteristics of the WS2 and WO3 thin films. Electrical properties of W/n-Si metal-semiconductor (MS) and W/WS2/n-Si and W/WO3/n-Si metal-interfacial layer-semiconductor (MIS) diodes are investigated using current-voltage (I-V) and capacitance-voltage (C-V) characteristics at various temperatures. It was found that I-V and C-V characteristics are strongly dependent on temperature and the interfacial WS2 and WO3 layers are significant roles for the electrical properties of W/WS2/n-Si and W/WO3/n-Si devices.

  AtıfScopus19·WoS20·OpenAlex17

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