[16p-A409-1~17] 6.1 Ferroelectric thin films

▲ [16p-A409-8] Compositional modification of epitaxial Pb(Zr,Ti)O₃ thin films for high-performance piezoelectric energy harvesters

〇SangHyo Kweon¹, Eun Ji Kim², Goon Tan³, Isaku Kanno¹ (1.Kobe Univ., 2.Korea Univ., 3.Osaka Metropolitan Univ.)

Keywords:Piezoelectric energy harvester, PZT, direct piezoelectric effect

To produce high-performance piezoelectric energy harvesters (PEH), piezoelectric materials with a large direct piezoelectric coefficient (e_31,f) and a small relative dielectric constant (ε_r,33) are required. In this study, PEHs were fabricated based on epitaxial Pb(Zr,Ti)O₃ (PZT) thin films. The epitaxial PZT thin films were deposited on Si substrates by an RF magnetron sputtering. The Zr/Ti ratio of the thin films was controlled by using sputtering targets with given compositions and by combining targets with different compositions. Meanwhile, the direct e_31,f values were evaluated by an unimorph cantilever method which is also applicable to the assessment of PEHs’ performances. The PZT cantilever of Zr/Ti = 58/42 exhibited a direct e_31,f of 10.4 C/m², along with a ε_r,33 of 285. According to the figure of merit (FOM) defined as (e_31,f)²/ε₀ε_r,33, the PZT cantilever had a value of 43 GPa. Moreover, at a resonant frequency of 421 Hz under an acceleration of 11 m/s², the PZT cantilever presented a high output power of 158.0 µW, which is very promising for the high-performance PEH applications.