A molybdenum (Mo)-doped zinc oxide thin film is deposited on a glass substrate by a rf magnetron sputtering technique. The structural and optical characteristics of ZnO:Mo (ZMO) thin films prepared with various deposition parameters are investigated. A series of SEM images obtained reveal that the average grain size of ZMO thin films is small and uniform. Energy dispersive spectroscopy analysis also verifies that traces of Mo are present in the as-grown thin films. The thicknesses of these ZMO films ranging from 150 to 390 nm are obtained by varying pertinent sputtering parameters. The average transmittance of ZMO thin films measured is more than 80% in the visible spectrum.
A UV sensor composed of a surface acoustic wave (SAW) device and a high-frequency amplifier was constructed using a Colpitts oscillator circuit. Zinc oxide (ZnO) films of SAW devices were prepared on lithium niobate substrates with various deposition temperatures to investigate their effect on the sensitivity of UV sensors. Larger grain sizes and a better chemical composition of the ZnO films were obtained at high-deposition temperatures rather than at low-deposition temperatures. An extreme frequency shift of 264 kHz and sensitivity of 0.21 kHz/(µW/cm2) were obtained for the ZnO-based SAW oscillator at the deposition temperature of 400 °C.
A main problem associated with piezoresistive pressure sensors is the cross sensitivity sensed among different temperature. The influence of temperature is manifested as a change in the span and offset of the sensor output. In this paper, a new temperature compensation technique for a silicon pressure sensor is presented. We combine two sensors, the piezoresistive bridge and the compensation one, together to instead of the original single piezoresistive pressure sensor circuit. There are many advantages of using the configured double bridge technique, such as eliminates the zero pressure offset, compensates for the output variation, and gives the sensor extreme low drift of the temperature. Besides, it covers a wider temperature and pressure range, reduce the prime cost of sensors, and lessen the size of finished products. The simulation and experimental results are matched to our theoretical analysis. The feasibility of the new configure is proved.