A study of Love wave devices in ZnO/Quartz and ZnO/LiTaO3 structures

Love wave devices are very promising for sensing applications because of high sensitivity. In this paper, ZnO thin films doped with lithium (Li) and magnesium (Mg) were deposited on the 42-45V ST-cut quartz and 36- YX-LiTaO3 substrates by RF magnetron sputtering technique. XRD, SEM, and AFM measurements investigated characteristics of the films. Under different conditions such as doping content, layer thickness, and substrate temperature, the phase velocity, temperature coefficient of frequency, electromechanical coupling coefficient and sensitivity of Love wave devices in ZnO/Quartz and ZnO/LiTaO3 structures are presented. The maximum sensitivities of ZnO/Quartz and ZnO/LiTaO3 are much higher than the SiO2/Quartz and SiO2/LiTaO3 structures reported. D 2005 Elsevier B.V. All rights reserved.

[1]  S. Buttgenbach,et al.  Properties of sensors based on shear-horizontal surface acoustic waves in LiTaO/sub 3//SiO/sub 2/ and quartz/SiO/sub 2/ structures , 2001, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[2]  M. Kadota.  Surface Acoustic Wave Characteristics of a ZnO/Quartz Substrate Structure Having a Large Electromechanical Coupling Factor and a Small Temperature Coefficient , 1997 .

[3]  W. Wlodarski,et al.  A layered surface acoustic wave ZnO/LiTaO3 structure with a WO3 selective layer for hydrogen gas sensing , 2003 .

[4]  M. Vellekoop,et al.  Viscosity sensing using a Love-wave device , 1998 .

[5]  M.J. Vellekoop,et al.  Analysis and optimization of Love wave liquid sensors , 1998, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[6]  Andrew G. Glen,et al.  APPL , 2001 .

[7]  S Hunklinger,et al.  Development of a surface acoustic wave immunosensor. , 1996, Analytical chemistry.

[8]  K. Yamanouchi,et al.  High temperature stable GHz-range low-loss wide band transducers and filter using SiO/sub 2//LiNbO/sub 3/, LiTaO/sub 3/ , 1995, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[9]  Min Han,et al.  Substrate dependent internal stress in sputtered zinc oxide thin films , 1992 .

[10]  Michael J. Vellekoop,et al.  A love wave sensor for (bio)chemical sensing in liquids , 1994 .

[11]  Vinay Gupta,et al.  Influence of postdeposition annealing on the structural and optical properties of sputtered zinc oxide film , 1996 .

[12]  G. L. Harding,et al.  A study of Love-wave acoustic sensors , 1996 .

[13]  Sheng-Yuan Chu,et al.  Physical and structural properties of ZnO sputtered films , 2002 .

[14]  Kalpathy B. Sundaram,et al.  Characterization and optimization of zinc oxide films by r.f. magnetron sputtering , 1997 .

[15]  Sheng-Yuan Chu,et al.  An investigation of the dependence of ZnO film on the sensitivity of Love mode sensor in ZnO/quartz structure. , 2003, Ultrasonics.

[16]  Wojtek Wlodarski,et al.  A novel Love-mode device based on a ZnO/ST-cut quartz crystal structure for sensing applications , 2002 .

[17]  N. Saito,et al.  Effect of shear horizontal leaky surface acoustic wave on selectivity for ethanol decomposition of a copper thin-film catalyst deposited on a positively polarized ferroelectric LiTaO3 single crystal , 1999 .

[18]  S. Chu,et al.  Study of preferred orientation of zinc oxide films on the 64°LiNbO3 substrates and their applications as liquid sensors , 2004 .

[19]  Hideki Yamamoto,et al.  ZnO thin films deposited on various LiNbO3 substrates by RF-sputtering , 2001 .

[20]  Chin‐Chong Tseng,et al.  Elastic Surface Waves on Free Surface and Metallized Surface of CdS, ZnO, and PZT‐4 , 1967 .

[21]  Dominique Rebière,et al.  Study of acoustic Love wave devices for real time bacteriophage detection , 2003 .

[22]  Florian Bender,et al.  Love-Wave Biosensors Using Cross-Linked Polymer Waveguides on LiTaO{sub 3} Substrates , 2000 .

[23]  S. Fujihara,et al.  Effects of Li and Mg doping on microstructure and properties of sol-gel ZnO thin films , 2001 .