UV sensing using surface acoustic wave device on DC sputtered ZnO monolayer

Zinc oxide (ZnO) thin films were deposited on silicon substrates by DC sputtering deposition. Thermal annealing was performed at up to 900 degrees C in N-2 for 30 min. The effect of annealing on the crystal quality was investigated using X-ray diffraction, photoluminescence (PL) spectra, atomic force microscopy, scanning electron microscopy, and piezoelectric measurements. The PL response improved considerably during annealing. The piezoelectricity (d(33)) of selected films was measured using laser interferometric measurements. It showed, that d(33) decreases with annealing temperature. A novel device, based on a SAW device, has been designed and fabricated for UV sensing. The sputtered ZnO monofilm has been optimised for both piezoelectric properties and UV sensing ability. The fabrication using electron beam lithography, Al evaporation and lift-off as well as constraints experienced during miniaturisation will be discussed. (c) 2006 Elsevier B.V. All rights reserved.