Title :
The study of InOx/ZnO/XZ LiNbO3 layered SAW devices for ozone sensing
Author :
Fechete, A.C. ; Ippolito, S.J. ; Kalantar-zadeh, K. ; Wlodarski, W. ; Holland, A.S. ; Galatsis, K. ; Kiriakidis, G. ; Katsarakis, N. ; Katharakis, M.
Author_Institution :
Sch. of Electr. & Comput. Syst. Eng., R. Melbourne Inst. of Technol., Vic., Australia
Abstract :
An investigation of layered surface acoustic wave (SAW) devices based on an InOx/ZnO/XZ LiNbO3 structure for sensing ozone (O3) is presented. Device structures are based on an XZ lithium niobate (LiNbO3) substrate with a 1.2 μm zinc oxide (ZnO) guiding layer. 40 and 200 nm thin films of indium oxide (InOx) provide the selectivity towards O3 gas. The sensor response features are analyzed in terms of response time, recovery time and response magnitude as a function of operating temperature. A high sensitivity with fast and stable responses towards O3 was achieved. Exceptionally large frequency shifts as high as 78.5 kHz were observed for O3 concentrations as low as 25 parts per billion (ppb) in air. Microstructural characterization of the InOx films by scanning electron microscopy (SEM) is also presented.
Keywords :
gas sensors; indium compounds; lithium compounds; ozone; piezoelectric devices; sensitivity; substrates; surface acoustic wave sensors; thin films; zinc compounds; 1.2 micron; 200 nm; 40 nm; InO-ZnO-LiNbO3; O3; XZ lithium niobate substrate; indium oxide; layered SAW devices; layered surface acoustic wave devices; microstructural characterization; operating temperature; ozone sensing; piezoelectric substrate; recovery time; response magnitude; response time; zinc oxide; Acoustic waves; Indium; Lithium niobate; Scanning electron microscopy; Sensor phenomena and characterization; Surface acoustic wave devices; Surface acoustic waves; Temperature sensors; Thin film devices; Zinc oxide;
Conference_Titel :
Sensors, 2004. Proceedings of IEEE
Print_ISBN :
0-7803-8692-2
DOI :
10.1109/ICSENS.2004.1426475
