Fast and wide-band response infrared detector using porous PZT pyroelectric thick film

Abstract

Porous lead zirconate titanate (PbZr0.3Ti0.7O3, PZT30/70) thick films and detectors for pyroelectric applications have been fabricated on alumina substrates by screen-printing technology. Low temperature sintering of PZT thick films have been achieved at 850°C by using Li2CO3 and Bi2O3 sintering aids. The microstructure of PZT thick film has been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dielectric properties were measured using HP 4284 at 1kHz under 25°C. The permittivity and loss tangent of the thick films were 94 and 0.017, respectively. Curie temperature of PZT thick film was 425°C as revealed by dielectric constant temperature measurement. The pyroelectric coefficient was determined to be 0.9×10−8Ccm−2K−1 by dynamic current measurement. Infrared detector sensitive element of dual capacitance was fabricated by laser directly write technology. Detectivity of the detectors were measured using mechanically chopped blackbody radiation. Detectivity ranging from 1.23×108 to 1.75×108(cmHz1/2W−1) was derived at frequency range from 175.5Hz to 1367Hz, and D*’s −3dB cut-off frequency bandwidth was 1.2kHz. The results indicate that the infrared detectors based on porous thick films have great potential applications in fast and wide-band frequency response conditions.