Pyroelectric and sensor properties of ferroelectric thin films for energy conversion

High pyroelectric coefficients and improved conversion effects were successfully demonstrated in highly (111)-oriented ferroelectric PZT 90/10 films on Pt/Si substrates. The strong preferred orientation exhibited by these films was obtained through controlled heat-treatment using a specially developed MOD process on Pt/Ti/SiO 2/Si substrates. Within the FE LT–FE HT phase transition range of 80∼100°C, the films exhibited significant changes in spontaneous polarization, by roughly a factor of 2 (∼ 7 μC cm −2). A pyroelectric current, correlated to a pyroelectric coefficient of 30±10 nC cm 2 K, was obtained around room temperature without poling treatment. A prototype pyroelectric transformer based on these films gave a voltage output of 0·8 volt from a 1 mm 2 area on a 1·0 μm thick film. Compared to bulk ceramics and thick films, these thin films also exhibited at least one order of magnitude higher working frequency.