Effect of annealing temperature on the sol-gel derived Pb(Zr0.3Ti0.7)O3 thin films for pyroelectric application

Lead zirconate titanate thin films by a sol-gel method are deposited on platinum coated silicon wafer for pyroelectric application. Annealing temperature is varied between 560 and 700 deg. C in order to optimize the detectivity figure of merit Fd=p/[c(εrε0 tan δ)1/2] (where p is pyroelectric coefficient, c is volume specific heat, εr is the relative dielectric constant, ε0 is dielectric constant of free space and tan δ is the dielectric loss tangent). Only perovskite crystalline structure are observed in all the films annealed in this temperature range. It is found that higher annealing temperature is beneficial for better pyroelectric property. The measured pyroelectric coefficient is increased from 220 μC m-2K-1 at 560 deg. C annealing temperature to 300 μC m-2K-1 at 700 deg. C annealing temperature. But dielectric constant is also found to increase with annealing temperature from 310 at 560 deg. C to 560 at 700 deg. C, which impairs the value of detectivity figure of merit. Another important parameter is dielectric loss tangent, which is found to decrease with annealing temperature from 0.025 at 560 deg. C to 0.011 at 700 deg. C. The calculated detectivity figure of merit increases with increasing annealing temperature from 560 to 640 deg. C and decreases with further increasing annealing temperature. The optimized annealing temperature is determined to be 640 deg. C, and the detectivity figure of merit is 16.6x10-6 Pa-1/2