The authors report the resonance frequency and the energy dissipation of single crystal diamond cantilevers with different dimensions, which were fabricated by ion implantation assisted technique. The resonance frequency well followed the inverse power law relationship with the length of the cantilevers and exhibited a high reproducibility with varying the dimensions. The energy dissipation decreased with increasing the cantilever length and saturated or reduced at a certain value. For the shorter cantilevers, clamping loss governed the energy dissipation. As the cantilever length increased to a certain value, defects relaxation or surface effect became dominant. The possible origins for these energy dissipations were discussed.

The use of oxygen in improving diamond quality has been investigated by comparing two (111) homoepitaxial diamond films deposited with ${\mathrm{H}}_{\mathrm{2}}{\mathrm{–CH}}_{\mathrm{4}}$ and ${\mathrm{H}}_{\mathrm{2}}{\mathrm{–CH}}_{\mathrm{4}}{\mathrm{–O}}_{\mathrm{2}}$ mixtures by microwave assisted chemical vapor deposition. The (111) diamond deposited using a ${\mathrm{H}}_{\mathrm{2}}{\mathrm{–CH}}_{\mathrm{4}}$ mixture showed surface cracks due to the presence of nondiamond phases as well as a significant amount of hydrogen and silicon impurities. The (111) diamond deposited using a ${\mathrm{H}}_{\mathrm{2}}{\mathrm{–CH}}_{\mathrm{4}}{\mathrm{–O}}_{\mathrm{2}}$ mixture showed an absence of hydrogen and silicon impurities and nondiamond phases, and exhibited a flat surface. The addition of oxygen is one of the suitable methods to produce high-quality (111) homoepitaxial diamond.

Hydrogen-terminated vacancies in Si+-implanted Si were studied by means of positron annihilation. After the Si+-ion implantation, hydrogen atoms were introduced into the damaged region using a hydrogen plasma [hydrogen-atom treatment (HAT)]. Monoenergetic positron beams were used to measure Doppler broadening spectra of the annihilation radiation and the lifetime spectra of positrons. It was found that the line shape parameter, S, corresponding to the annihilation of positrons trapped by vacancy-type defects, decreased after HAT. This was attributed to the trapping of positrons by H-decorated vacancy-type defects. Isochronal annealing experiments revealed a strong correlation between positron annihilation parameters and Raman intensities of Si–H, suggesting that hydrogen atoms are released from vacancy-type defects after annealing at 600 °C

We show that the variation of the structural unit in tellurite glasses is due to the charge transfer from modifier atoms to ${\mathrm{TeO}}_6$ octahedra with use of first-principles molecular-orbital calculations. Mulliken overlap populations indicate that the oxygen coordination number of a Te atom reduces as the charge transfer progresses. This is consistent with the trend found in metal tellurite structures. Orbital-overlap population analysis reveals that the transferred electrons to the Te-O antibonding orbital cause breaking in the Te-O bonds and lead to reducing the coordination number of the Te atom. The bond ionicity and charge states of a Te atom and an O atom in α-${\mathrm{TeO}}_2$ are also presented.

We have designed a new ternary structure to enhance the sensing properties of WS₂ nanosheet (NS)-based gas sensors at room temperature (RT) in self-heating mode. SnO₂ nanowires (NWs, 10–30 wt%) were added to WS₂ NSs and then Au nanoparticles (NPs) were deposited on the surface of the resulting composites by UV irradiation. The Au-decorated 10 wt% SnO₂–WS₂ composition showed the highest gas sensing properties. The presence of SnO₂ NWs on the WS₂ NSs effectively enhanced the diffusion and adsorption of gas species into deeper parts of the gas sensor. Furthermore, the chemical sensitization of Au (increase in oxygen ionosorption; spillover effect and catalytic effect towards CO) contributed to an enhanced response to CO gas. Gas sensing tests performed in the self-heating mode demonstrated the possibility of realizing a low-voltage, low-power-consumption CO gas sensor based on the Au-decorated 10 wt% SnO₂–WS₂. The sensor response under 60% relative humidity (RH) conditions was 84% of that under dry conditions, which shows that CO sensing is possible in wet environments at room temperature operation.