The combination of the sol-gel method and the hydrothermal process in microwave system can be successfully used to prepare polycrystalline PZT thin films at the temperature of 160◦C in 30ml 2M KOH + 0.2M Pb(NO3)2 solution. The hydrothermal annealing in microwave system can shorten the reaction time and improve the efficiency. Because the reaction in each vessel uses only 30ml solution, the annealing method can also be attributed to fit the requirement of green energy. The hydrothermal treatment mechanism, for the first time, is proposed to follow dissolution-reaction-crystallization below.
Pb(OH)2 → PbO + H2O Pb(OH)2 → Pb2+ + 2OH
-Δ
Pb2+ + 2OH- → PbO + H2O
The PZT sensors, without coating anything, showed the ability to detect organic vapors like alcohol and toluene. The curve of the frequency shifts and the saturated pressure almost match together for alcohol. The toluene gas can also be detected in the similar way. The sensing performance of the PZT sensor is quite reliable. The resonant frequency of the sensor is about 30MHz and the sensing limit is estimated to be about 1ppm.
Δ
Since the PZT sensors are sensitive and reliable in sensing volatile vapor, we plan to improve the efficiency by the array design. The developed PZT sensor can be extended to detect other biomolecules like DNA or proteins in the future.
Reference
[1] J. F. Tressler, S. Alkoy and R. E. Newnham, “Piezoelectric Sensors and Sensor Materials”, Journal of Electroceramics, 2, 257-272 (1998)
[2] C.K. O’Sullivan and G.G. Guilbault, “Commercial quartz crystal microbalances – theory and applications”, Biosensors & Bioelectronics, 14, 663-670, (1999)
[3] http://www.txc.com.tw/in04/in4_01.html
[4] M. Rodahl, F. Höök, A. Krozer, P. Brzezinski and B.Kasemo, “Quartz crystal
microbalance setup for frequency and Q-factor measurements in gaseous and liquid environments”, Review of Scientific Instruments, 66, 3924-3930, (1995)
[5] M. Rodahl and B. Kasemo, “A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance”, Review of Scientific Instruments, 67, 3238-3241, (1996)
[6] B. D. Vogt, E. K. Lin, W. L. Wu and C. C. White, “Effect of Film Thickness on the Validity of the Sauerbrey Equation for Hydrated Polyelectrolyte Films”, Journal of Physical Chemistry B, 108, 12685-12690, (2004)
[7] T. D. Hadnagy, “Materials and production characterization requirements for the
production of FRAM(R) memory products”, Integrated Ferroelectrics, 18, 1-17, (1997) [8] B. Noheda, J. A. Gonzalo, L. E. Cross, R. Guo, S. E. Park, D. E. Cox and G. Shirane,
“Tetragonal-to-monoclinic phase transition in a ferroelectric perovskite: The structure of PbZr0.52Ti0.48O3”, Physical Review B, 61, 8687-8689, (2000)
[9] P. Birounvand, M. H. Berntsen, J. Penttilä, S. Shokatloo and M. Wahlqvist, “Biosensors based on piezoelectric materials: Indoor air monitoring and detection of bacterial spores”, Royal Institute of Technology, (October 2005)
[10] R. E. Alonso, A. L. García, A. Ayala and P. de la Presa, “Temperature dependence of the nuclear quadrupole interaction at Zr–Ti sites in PbZrxTi.1−xO3 in the Zr-rich
rhombohedral and cubic phases”, Journal of Physics-Condensed Matter, 10, 2139-2153,
(1998)
[11] P. Muralt, “Ferroelectric thin films for micro-sensors and actuators: a review”, Journal of Micromechanics and Microengineering, 10, 136-146, (2000)
[12] C. M. Foster, G. R. Bai, R. Csencsits, J. Vetrone, R. Jammy, L. A. Wills, E. Carr and J.
Amano, “Single-crystal Pb(ZrxTi1-x)O3 thin films prepared by metal-organic chemical vapor deposition: Systematic compositional variation of electronic and optical
properties”, Journal of Applied Physics, 81, 2349-2357, (1997)
[13] Y. Sakashita, H. Sagawa, K. Tominaga and M. Okada, “Dependence of
electrical-properties on film thickness in Pb(ZrXTi1-X)O3 thin-films produced by metalorganic chemical-vapor-deposition”, Journal of Applied Physics, 73, 7857-7863, (1993)
[14] K. Nagashima and H. Funakubo, “Composition control of Pb(ZrxTi1-x)O3 thin films prepared by metalorganic chemical vapor deposition”, Japanese Journal of Applied Physics Part 1, 39, 212-216, (2000)
[15] B. S. Kwak, E. P. Boyd and A. Erbil “MOCVD of PbTiO3 thin films”, Applied Physics Letters, 53, 1702–1704, (1988)
[16] I. Kanno, S. Fujii, T. Kamada and R. Takayama, “Piezoelectric properties of c-axis oriented Pb(Zr,Ti)O3 thin films”, Applied Physics Letters, 70, 1378-1380, (1997) [17] I. Taguchi, A. Pignolet, L. Wang, M. Proctor, F. Lavy and P. E. Shmid,
“Raman-scattering from PbTiO3 thin-films prepared on silicon substrates by radio-frequency sputtering and thermal-treatment”, Journal of Applied Physics, 73, 394-399, (1993)
[18] T. Hase, T. Sakuma, Y. Miyasaka, K. Hirata and N. Hosokawa, “Preparation of Pb(Zr, Ti)O3 thin-films by multitarget sputtering”, Japanese Journal of Applied Physics Part 1, 32, 4061-4064, (1993)
[19] S. B. Krupanidhi, N. Maffei, M. Sayer and K. El-Assal “RF planar magnetron
sputtering and characterization of ferroelectric PZT films”, Journal of Applied Physics, 54, 6601–6609, (1983)
[20] K. Sreenivas, M. Sayer and P. Grarett et al, “Properties of dc magnetron-sputtered PZT thin films”, Thin Solid Films, 172, 251–267, (1989)
[21] T. Nakamura, Y. Nakao, A. Kamisawa and H. Takasu, “Preparation of Pb(Zr,Ti)O3
thin-films on Ir and IrO2 electrodes”, Japanese Journal of Applied Physics Part 1, 33, 5207-5210, (1994)
[22] T. Astuki, N. Soyama, G. Sasaki, T. Yonezawa, K. Ogi, K. Sameshima, K. Hoshiba, Y.
Nakao and A. Kamisawa, “Surface-morphology of lead-based thin-films and their properties”, Japanese Journal of Applied Physics Part 1, 33, 5196-5200, (1994)
[23] C. J. Kim, D. S. Yoon, J. S. Lee, C. G. Choi and K. S. Nol, “Effects of substracte effect of substracte and bottom electrodes on the phase-formation of lead-zirconate-titanate thin films prepared by the sol-gel method”, Japanese Journal of Applied Physics Part 1, 33, 2675-2678, (1994)
[24] Y. C. Zhou, Z. Y. Yang and X. J. Zheng, “Residual stress in PZT thin films prepared by pulsed laser deposition”, Surface & coatings technology, 162, 202-211, (2003) [25] M. C. Kim, J. W. Choi, S. J. Yoon, K. H. Yoon and H. J. Kim, “Thickness dependence
of Pb(Zr0.52Ti0.48)O3 films prepared by pulsed laser deposition”, Japanese Journal of Applied Physics Part 1, 41, 3817-3821, (2002)
[26] Y. Masuda, T. Nozaka , “The influence of various upper electrodes on fatigue
properties of perovskite Pb(Zr,Ti)O3 thin films”, Japanese Journal of Applied Physics Part 1, 42, 5941-5946, (2003)
[27] R. Gupta, M. P. Srivastava, V. R. Balakrishnan, R. Kodama and M. C. Peterson,
“Deposition of nanosized grains of ferroelectric lead zirconate titanate on thin films using dense plasma focus”, Journal of physics D, 37, 1091-1094, (2004)
[28] Z. WEI, K. Yamashita and M. Okuyama “Preparation of Pb(Zr0.52TiO0.48)O3 thin films
at low-temperature of less than 400◦C by hydrothermal treatment following sol-gel deposition”, Japanese Journal of Applied Physics Part 1, 40, 5539-5542, (2001) [29] Z. WEI, K. Yamashita and M. Okuyama, “low temperature preparation of sol-gel PZT
thin film annealed at 160°C by hydrothermal method”, Applications of ferroelectrics, 2, 921-924, ISAF 2000. Proceedings of the 2000 12th IEEE International Symposium, (2000)
[30] E. K. Barnhardt and B. L. Hayes, “Performing microwave-assisted reactions at low temperatures preliminary results”, the 226th ACS National Meeting New York, NY, (September 9, 2003)
[31] E. Nest, M. Collins, Introduction to microwave sample prearation theory and pratice, (1998)
[32] H. M. Kingston and S. J. Haswell, Microwave-Enhance Chemical,American Chemical Society, Washington DC, (1997)
[33] M. Ferrari, V. Ferrari, D. Marioli, A.Taroni, M. Suman and E. Dalcanale,
“Cavitand-coated PZT resonant piezo-layer sensors: properties, structure, and comparison with QCM sensors at different temperatures under exposure to organic vapors”, Sensors and Actuators B, 103, pp. 240-246, (2004)
[34] Q. M. Wang, Y. Ding, Q. Chen and M. Zhao, “Crystalline orientation dependence of nanomechanical properties of Pb(Zr0.52Ti0.48)O3 thin films”, Applied Physics Letters, 86, 2005