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International Journal of Photoenergy
Volume 2014 (2014), Article ID 270186, 6 pages
http://dx.doi.org/10.1155/2014/270186
Research Article

Love Wave Ultraviolet Photodetector Fabricated on a TiO2/ST-Cut Quartz Structure

1Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan
2Institute of Electro-Optical and Materials Science, National Formosa University, Yunlin 632, Taiwan

Received 30 May 2014; Accepted 20 June 2014; Published 10 July 2014

Academic Editor: Teen-Hang Meen

Copyright © 2014 Walter Water et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A TiO2 thin film deposited on a 90° rotated 42°45′ ST-cut quartz substrate was applied to fabricate a Love wave ultraviolet photodetector. TiO2 thin films were grown by radio frequency magnetron sputtering. The crystalline structure and surface morphology of TiO2 thin films were examined using X-ray diffraction, scanning electron microscope, and atomic force microscope. The effect of TiO2 thin film thickness on the phase velocity, electromechanical coupling coefficient, temperature coefficient of frequency, and sensitivity of ultraviolet of devices was investigated. TiO2 thin film increases the electromechanical coupling coefficient but decreases the temperature coefficient of frequency for Love wave propagation on the 90° rotated 42°45′ ST-cut quartz. For Love wave ultraviolet photodetector application, the maximum insertion loss shift and phase shift are 2.81 dB and 3.55 degree at the 1.35-μm-thick TiO2 film.