Enhanced performance of pyroelectric microsensors through the introduction of nanoporosity

Sol-gel process has successfully been applied for the deposition of porous PbZrxTi1−xO3 (x=0.45, 0.15) thin films on platinized silicon wafers. Addition of a polymer as a volatile phase to the precursor sol prior to spin coating has been proved an excellent method to synthesize PZT-porous films. Introduction of pores creates a matrix void composite resulting in high figures of merit for pyroelectric applications. The dielectric constant was found to be strongly dependent to the porosity, whereas the pyrocoefficient changes moderately with porosity. The relative permittivity can be decreased down to 150 and 95 for PZT films with Zr/Ti ratio of 45/55 and 15/85 respectively, and the figures of merit Fv and Fd values for PZT (Zr/Ti=15/85) films can be increased up to 1.95 and 139 μC/m2 K, respectively by incorporating a nanoporous structure in films.