Properties of PbTiO₃, La-modified PbTiO₃ and Pb(Zr,Ti)O₃ thin films and their application to infrared detectors

The structure and properties of PbTiO₃, La-modified PbTiO₃ and Pb(Zr,Ti)O₃ ferroelectric thin films and multilayer pyroelectric thin films applied to infrared detectors were investigated. A PbTiO₃ thin film with fine crystal grains has low dielectric constant and loss tangent, and its pyroelectric coefficient is 1. 6 × 10^-8 C/cm² K. A multilayer pyroelectric thin film is introduced to reduce thermal loss from the pyroelectric layer to the substrate. A porous SiO₂ thin film with very low thermal conductivity was prepared and used as a thermal insulating layer. Experimental results show that the multilayer pyroelectric thin film can improve the pyroelectric response of a thin film detector remarkably at low frequency, and is a promising candidate for infrared detectors.