Pyroelectric properties of sol-gel derived lanthanum modified lead titanate thin films

Lanthanum-modified lead titanate (PLT) thin films were fabricated on Pt/Ti/SiO2/Si substrate using the sol-gel method and rapid thermal annealing technique. The pyroelectric coefficient, and the infrared responsivity and the detectivity of the films were measured using static and dynamic methods, respectively. The ferroelectric properties were also measured. The pyroelectric coefficient increased from 1.3 to 2.5 nC/cm(2) . K with increasing La content. However, these low coefficients of PLT films are due to their crystal quality and orientations. The infrared response properties of PLT films depended on their thermal time constants. tau(t) (thermal time constant) for the PLT films decreased with the La contents increasing. The effects of back surface etching on the responsivity and the detectivity were also discussed.