%0 Journal Article
%T Synthesis and Characterization of Pb(Zr , Ti )O -Pb(Nb , Zn )O Thin Film Cantilevers for Energy Harvesting Applications
%A E. M. A. Fuentes-Fernandez
%A W. Debray-Mechtaly
%A M. A. Quevedo-Lopez
%A B. Gnade
%A E. Leon-Salguero
%A P. Shah
%A H. N. Alshareef
%J Smart Materials Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/872439
%X A complete analysis of the morphology, crystallographic orientation, and resulting electrical properties of Pb(Zr0.53,Ti0.47) Pb(Nb1/3, Zn2/3)O3 (PZT-PZN) thin films, as well as the electrical behavior when integrated in a cantilever for energy harvesting applications, is presented. The PZT-PZN films were deposited using sol-gel methods. We report that using 20% excess Pb, a nucleation layer of PbTiO3 (PT), and a fast ramp rate provides large grains, as well as denser films. The PZT-PZN is deposited on a stack of TiO2/PECVD SiO2/Si3N4/thermal SiO2/Poly-Si/Si. This stack is designed to allow wet-etching the poly-Si layer to release the cantilever structures. It was also found that the introduction of the poly-Si layer results in larger grains in the PZT-PZN film. PZT-PZN films with a dielectric constant of 3200 and maximum polarization of 30£¿¦ÌC/cm2 were obtained. The fabricated cantilever devices produced ~300¨C400£¿mV peak-to-peak depending on the cantilever design. Experimental results are compared with simulations. 1. Introduction The ability to retrofit systems with power consuming electronics without having to consider issues associated with providing an independent power source offers a significant advantage for devices in hard to reach locations [1]. In the past few years there has been an increase in research on small wireless electronic devices [1¨C3]. Mechanical vibrations have received attention as a potential source of power for sensors and wireless electronics in a wide variety of applications [4]. To accomplish this, improving the piezoelectric material used in the cantilever is of paramount importance [5]. Piezoelectric materials are widely used for various devices, including multilayer capacitors, sensors, and actuators [2, 3, 6]. By the 1950s, the ferroelectric solid solution Pb(Zr1£¿x Tix)O3 (PZT) was found to have exceptionally high dielectric and piezoelectric properties for compositions close to the morphotrophic phase boundary (MPB) [7, 8]. Research to improve the PZT properties, from the material and electrical standpoint, has been mainly accomplished by doping conventional PZT with different elements to ¡°relax¡± the material [5, 9]. Previous investigations on the dielectric and electrical properties of many ceramic systems, such as barium titanate (BT), lead zirconate titanate (PZT), lead magnesium niobate (PMN), lead titanate (PT), PMN-PT, PZT-BT, and PMN-PZT have demonstrated the importance of the subject [10¨C13]. Recently, there has been a great deal of interest in the lead zirconate titanate-lead zinc niobate
%U http://www.hindawi.com/journals/smr/2012/872439/