Characterization of ZnO films of surface acoustic-wave oscillators for ultraviolet sensing applications

Abstract

A UV sensor composed of a surface acoustic wave ͑SAW͒ device and a high-frequency amplifier was constructed using a Colpitts oscillator circuit. Zinc oxide ͑ZnO͒ 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/ ͑W/cm 2 ͒ were obtained for the ZnO-based SAW oscillator at the deposition temperature of 400°C. © 2010 Society of Photo-Optical Instrumentation Engineers.

Piezoelectric Response Evaluation of ZnO Thin Film Prepared by RF Magnetron Sputtering

“…Piezoelectric materials have been attracting considerable attention because of their potential applications for acoustic devices [1], micro motors [2], AFM cantilevers [3], UV detectors [4][5] or chemical sensors [6]. The most important parameter of piezoelectric materials is piezoelectric coefficient (d33).…”

Ultraviolet Sensing System Using ZnO Based Surface Acoustic Wave Oscillator

“…This may lower the threshold of UV excitonic lasers and be used in the integrated circuit system including and the tunable UV photodetectors. Various methods have been used to achieve the UV sensor such as photoconducting effect (1) , metal semiconductor Schottky barriers (2) , and the frequency response of SAW oscillator (3)(4) . SAW devices are very sensitive to surface changes, because in SAW devices a high density of acoustic energy propagates in the near-surface region of a piezoelectric.…”