Pyroelectric, ferroelectric and dielectric properties of Mn and Sb-doped PZT thin films for uncooled IR detectors

Mn and Sb-doped Pb(Zr,Ti)O-3 (PMSZT)/YBa2Cu3O7-y (YBCO) heterostructures gr own on Si substrates have been investigated for IR detector arrays. The epi taxial PMSZT films deposited on c-oriented YBCO conducting electrodes show "seIf polarization" behavior and high IR responsivity even without poling. An asymmetric hysteresis loop and C-V curve show that the original polariza tion state of the capacitors is pointing towards the top electrode in the P MSZT film, and perpendicular to the YBCO thin film. Doping with Mn and Sb h as been shown to enhance the pyroelectric and dielectric properties of PZT for enhanced IR sensitivity. The PMSZT IR detectors were examined for their pyroelectric coefficient and their detectivity D*. The PMSZT thin films ha ve relatively high pyroelectric coefficient of 45 nC cm(-2) K at 25 degrees C and 148 nC cm(-2) K at 90 degrees C. The PMSZT detector shows detectivit y D* values from 2.5 x 10(8) to 6.0 x 10(8) cmHz(1/2) W-1 in the 2.5-19.5 m u m wavelength range. (C) 1998 Elsevier Science S.A. All rights reserved.