Sol-gel PZT and Mn-doped PZT thin films for pyroelectric applications

Thin films of ferroelectric lead zirconate titanate (PbZr0.3Ti0.7O3 PZT30/70) and manganese-doped lead zirconate titanate ((Pb(Zr0.3Ti0.7)(1-x)Mn-x)O-3, where x = 0.01, PM01ZT30/70; and x = 0.03, PM03ZT30/70) have been prepared using sol-gel processing techniques. These materials can be used as the pyroelectric thin films in uncooled infrared detectors. The thin films were prepared via a sol-gel route based on a hybrid solvent of methanol and ethanol with acetic acid, ethanolamine and ethylene glycol as additives. The final solution is non-moisture sensitive and stable. Films deposited on Pt/Ti/SiO2/Si substrates and annealed on a hot plate at 500-530 degreesC for a few minutes were seen to fully crystallize into the required perovskite phase and showed excellent ferroelectric behaviour, demonstrated by reproducible hysteresis loops (P-r = 33-37 muC cm(-2), Ec(+) = 70-100 kV cm(-1), Ec(-) = -170 to -140 kV cm(-1)). The pyroelectric coefficient (p) was measured using the Byer-Roundy method. At 20 degreesC, p was 2.11 X 10(-4) C m(-2) K-1 for PZT30/70, 3.00 X 10(-4) C M-2 K-1 for PM01ZT30/70 and 2.40 X 10(-4) C M-2 K-1 for PM03ZT30/70 thin films. The detectivity figure-of-merit (F-D) was 1.07 X 10(-5) Pa-0.5 for PZT30/70, 3.07 X 10(-5) Pa-0.5 for PM01ZT30/70 and 1.07 X 10(-5) Pa-0.5 for PM03ZT30/70. These figures compare well with values reported previously.