Polycrystalline ZnO Films Deposited on Glass by RF Reactive Sputtering

Polycrystalline ZnO films were prepared on glass wafer using Zn targets by radio frequency(RF)reactive sputtering technique under different deposition conditions.X-ray diffraction (XRD) and optical transmittance spectrum were employed to analyze the structure and optical character of the films.The strain and stress in films, as well as the packing density are calculated in terms of refractive index of films measured with an elliptic polarization analyzer.It is the deposition conditions that have great effects on the structural and optical properties of ZnO films.Under the optimal conditions,the only evident peak in XRD spectrum was (002) peak with the full width at half maximum (FWHM) of 0.20° showing the grain size of 42.8 nm.The packing density,the stress in (002) plane and the average optical transmittance in the visible region were about 97%,-1.06×10~9 N/m^2 and 92%, respectively.

Tribological performance under different environments of Ti-C-N composite films for marine wear-resistant parts

The need for reducing the wear in mechanical parts used in the industry makes self-lubricant films one of the sustainable solutions to achieve long-term protection under different environmental conditions.The purpose of this work is to study the influence of C additions on the tribological behavior of a magnetron-sputtered TiN film in air,water,and seawater.The results show that the addition of C into the TiN binary film induced a new amorphous phase,and the films exhibited a dual phase of fcc(face-centered cubic)-TiN and amorphous carbon.The antifriction and wear-resistance properties were enhanced in air and water by adding 19.1at%C.However,a further increase in the C concentration improved anti-frictional properties but also led to higher wear rates.Although the amorphous phase induced microbatteries and accelerated the corrosion of TiN phases in seawater,the negative abrasion state was detected for all Ti-C-N films due to the adhesion of the tribocorrosion debris on the wear track.

An MWCNT-doped SnO_2 thin film NO_2 gas sensor by RF reactive magnetron sputtering

An MWCNT-doped （multi-walled carbon nanotube） Sn02 thin film NO2 gas sensor, prepared by radio frequency reactive magnetron sputtering, showed a high sensitivity to ultra-low concentrations of NO2 in the parts per billion range. X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy （SEM） characterizations indicated that the MWCNTs were affected by the morphology of the SnO2 thin film and the particle size. The properties of the MWCNT-doped SnO2 sensor, such as sensitivity, selectivity, and response-recovery time, were investigated. Experimental results revealed that the MWCNT-doped SnO2 thin film sensor response to NO2 gas depended on the operating temperature, NO2 gas concentration, thermal treatment conditions, film thickness, and so on. The mechanism of the gas-sensing property of the MWCNT-doped SnO2 thin film sensor was investigated and showed that the improved gas-sensing performance should be attributed to the effects between MWCNTs （p-type） and SnO2 （n-type） semiconductors.

Preparation of AlN thin films for film bulk acoustic resonator application by radio frequency sputtering

Aluminum nitride （AlN） thin films with high c-axis orientation have been prepared on a glass substrate with an Al bottom electrode by radio frequency （RF） reactive magnetron sputtering. Based on the analysis of Berg＇s hysteresis model, the improved sputtering system is realized without a hysteresis effect. A new control method for rapidly depositing highly c-axis oriented AlN thin films is proposed. The N2 concentration could be controlled by observing the changes in cathode voltage, to realize the optimum processing condition where the target could be fixed stably in the transition region, and both stoichiometric film composition and a high deposition rate could be obtained. Under a 500 W RF power of a target with a 6 cm diameter, a substrate temperature of 450 ℃, a target-substrate distance of 60 mm and a N2 concentration of 25%, AlN thin film with preferential （002） orientation was deposited at 2.3 μm/h which is a much higher rate than previously achieved. Through X-ray diffraction （XRD） analysis, the full width at half maximum （FWHM） of AlN （002） was shown to be about 0.28°, which shows the good crystallinity and crystal orientation of AlN thin film. With other parameters held constant, any increase or decrease in N2 concentration results in an increase in the FWHM of AlN.