High output performance of piezoelectric energy harvesters using epitaxial Pb(Zr, Ti)O-3 thin film grown on Si substrate

Abstract

For a high power density in piezoelectric energy harvesters, both a large direct piezoelectric coefficient (e(31,)(f)) and a small relative permittivity constant (epsilon(r,33)) are required. This study proposed an energy harvesting device made of an epitaxial Pb(Zr, Ti)O-3 (PZT) thin film grown on a Si substrate. The epitaxial PZT thin film is deposited on the Si substrate by RF magnetron sputtering. The epitaxial PZT thin film grown on Si substrate has a epsilon(r,33) constant of 318. The output voltage as a function of input displacement was measured using a shaker to evaluate the direct e(31,)(f) coefficients and energy harvester output characteristics. According to the figure of merit defined as (e(31,)(f))(2)/epsilon(0)epsilon(r,33), the epitaxial PZT/Si cantilever is 32 GPa. At a resonant frequency of 373 Hz under an acceleration of 11 m/s(2), the epitaxial PZT/Si cantilever has a high output power of 40.93 mu W and power density of 108.3 mu W/cm(2)/g(2) without any damage, which is very promising for high power energy harvester applications. Published under an exclusive license by AIP Publishing.