Pyroelectric PZT/PMNZTU composite thick films

Uranium doped lead magnesium niobate-lead zirconate titanate (PMNZTU) composite thick films have been fabricated on silicon substrates using a composite sol-gel technique. A slurry, made up of PMNZTU powder and PZT sol, was spun onto a silicon substrate and fired to yield a porous skeletal ceramic structure. Subsequent sol infiltration and pyrolysis was used to modify the density of the films prior to final sintering at 710 °C. Pyroelectric and dielectric properties have been measured as a function of sol infiltration. The pyroelectric coefficients (p_max = 2.74 C m^-2 K^-1) of the composite thick films were found to be comparable to tape cast and monolithic ceramics of similar composition (2.8 and 3.0 C m^-2 K^-1, respectively). Maximum figures-of-merit (FOM) (F_V = 3.45 × 10^-2 m² C^-1, F_D = 1.01 × 10^-5 Pa^-1/2), calculated using the electrical properties of the thick films, can be compared with those of screen printed thick films (F_V = 2.7-3.9 × 10^-2 m² C^-1, F_D = 0.8-1.1 × 10^-5 Pa^-1/2) processed at temperatures of approximately 1100 °C. The ability to directly integrate thick pyroelectric films onto substrates at temperatures as low as 710 °C, while maintaining competitive figures-of-merit is of considerable interest for future device applications.