Search

W–C thin films were prepared by non-reactive magnetron co-sputtering simultaneously from pure tungsten and carbon targets in an argon atmosphere at room temperature on Si(100) substrate. The main purpose of the present work was to investigate the influence of deposition method and annealing process on structural and electrical properties of the tungsten carbide thin films. The experimental results show that the growth rate of films was about 5.46 nm/min; the films have spherical granular structure. Hexagonal W2C appeared when the annealing temperature was 700 and 800°C and W : C atomic ratio of 1.18. Moreover, grain size of W2C films was about 8.1 and 11.7 nm after annealing at 700 and 800°C, respectively. Resistivity of films was relatively high, possibly due to the presence of excess carbon in the films not bound with tungsten, verified by the Raman spectrum.

In this work, Zn/ZnO composite photocatalyst was successfully synthesized by simple hydrothermal method. Photocurrent test shows that the presence of Zn can effectively improve the light response of composites. Electrochemical impedance spectroscopy indicates that Zn/ZnO has higher point and separation efficiency and faster carrier transmission. Degradation tests of methyl orange showed that Zn/ZnO had higher degradation efficiency than commercial ZnO. In the same time, Zn/ZnO can degrade nearly 90% of methyl orange, while commercial zinc oxide has less than 10%. Meanwhile, the photocatalyst synthesized in the test of photocatalytic removal of NO also shows higher photocatalytic activity. Compared with commercial ZnO, which removed 48% of NO in 20 min, Zn/ZnO could remove 74% of NO in 8 min, and NO will be further oxidized to NO3− after being oxidized to NO2, which can effectively reduce secondary pollution in the reaction process. These results indicate that Zn/ZnO composite photocatalysts have high photocatalytic activity in both solid–liquid and gas–solid systems. Photodegradation of MO (a), and NO removal (b) photocatalytic mechanism of Zn/ZnO under irradiation.

Titanium carbide (TiC) thin films were prepared by non-reactive simultaneous double magnetron sputtering. After deposition, all samples were annealed at different temperatures under high-vacuum conditions. This paper mainly discusses the influence of deposition methods and annealing temperatures on microstructure, surface topography, bonding states and electrical resistivity of TiC films. XRD (X-ray diffraction) results show that TiC thin films can still form crystals without annealing, and the crystallinity of thin films is improved after annealing. The estimated grain size of the TiC films varies from 8.5 nm to 14.7 nm with annealing temperature. It can be seen from SEM (scanning electron microscope) images that surfaces of the films are composed of irregular particles, and when the temperature reaches to 800 °C, the shape of the particles becomes spherical. Growth rate of film is about 30.8 nm/min. Oxygen-related peaks were observed in XPS (X-ray photoelectron spectroscopy) spectra, which is due to the absorption of oxygen atoms on the surface of the film when exposed to air. Raman spectra confirm the formation of TiC crystals and amorphous states of carbon. Resistivity of TiC films decreases monotonically from 666.73 to 86.01 μΩ·cm with the increase in annealing temperature. In brief, the TiC thin films prepared in this study show good crystallinity, thermal stability and low resistivity, which can meet the requirements of metal gate applications.