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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:46 |
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Conference: Bucharest University Faculty of Physics 2002 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Pt/Ni AND Pd/Ni THIN FILMS BASED GAS SENSORS
Authors:
P. Verardi1, F. Craciun1, C. Grigoriu2, D.G. Matei2, N.D. Scarisoreanu2, K. Yatsui3, H. Suematsu3, T. Suzuki3, A. Andrei4, M. Dinescu2
Affiliation:
1 IDAC- CNR, Rome, Italy, 2 NILPRP Bucharest, Romania, 3 EEDRI, Nagaoka University of Technology, Nagaoka, Japan, 4 INR, Pitesti, Romania
E-mail
Keywords:
Abstract:
A Surface Acoustic Wave (SAW) device containing a delay line consisting of two SAW transducers deposited on a silicon substrate with a piezoelectric overlayer and a top continuous floating electrode was realized. ZnO piezoelectric layers having a thickness of 2.5 mm (for a desired wavelength, l = 50 mm) have been deposited on Cr-Au interdigital transducers (ID) (1000 Å thickness) grown by thermal evaporation on (100) silicon substrate. An Al floating (top) electrode was deposited onto the ZnO layer in the zones overlapping the ID regions. The free silicon area in-between the two ID transducers was covered with different sets of membranes of Pt/Ni and Pd/Ni. ZnO films were grown by laser ablation of Zn target in oxygen and metallic membranes by alternative laser ablation of single targets. X-ray diffraction spectra are prezented. Scanning electron microscopy shows smooth surface for films prepared using UV laser wavelengths (l= 265 and 355 nm, respectively) for laser ablation. Very small traces of nickel oxide have been evidenced by XPS studies on films deposited for pressures superior to 10-4 mbar. Electric responses of the test structures have been tested by network analyzer HP 8753A in amplitude format S11 and S12. The quality of the ZnO film has been controlled by piezoelectric probe.
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