Fatigue characteristic and pyroelectric properties of highly (1 1 1)-oriented Nb doped Pb(Zr_0.2,Ti_0.8)O₃ thin films with Pb_0.8La_0.1Ca_0.1Ti _0.975O₃ seed layer prepared by a sol-gel route

A series of highly (1 1 1)-oriented tetragonal Nb-doped Pb(Zr _0.2Ti_0.8)O₃ (PNZT) films with and without Pb_0.8La_0.1Ca_0.1Ti_0.975O₃ (PLCT) seed layer were deposited on the Pt(1 1 1)/Ti/SiO₂/Si substrates by sol-gel processing; it was found the pyroelectric properties and fatigue resistance characteristics of PNZT films could be improved by introducing PLCT seed layer. Because the rough surface structures of 5 nm-thick PLCT seed layer can offer nucleation sites to reduce activation energy for the crystallization and lead to the polarization response easily, a large pyroelectric coefficient (460 μC/(m² K)) and a high figure-of-merit (F_d = 161 μC/(m² K)) was obtained for PLCT/PNZT/PLCT structure film. It was also found that PLCT seed layer could act as a capacitive interface layer possibly compensating for the vacancy-type defects from PNZT film effectively, which results in enhanced fatigue resistance characteristics of PLCT/PNZT/PLCT structure film.