Noise and specific detectivity of pyroelectric detectors using lead titanate zirconate (PZT) thin films

Pyroelectric infrared detectors using sol-gel deposited lead zirconate titanate (PZT) thin films were fabricated. It was found that specific detectivity D* of the detector is a strong function of the modulation frequency of the incident radiation. Noise plays an important role at low frequencies ( < 20 Hz). When the modulation frequency is low ( < 10 Hz), the noise is dominated by 1/f noise. Johnson noise dominates the noise at frequencies higher than 10 Hz. This characteristic can be clearly seen from the noise-frequency spectrum. A one-dimensional heat conduction theoretical model was used to simulate the dynamic responses of the pyroelectric IR detector. The simulated results fitted quite well with the experimental results. D* of the detector was predicted with the assumption that the Johnson noise was the dominating noise source. (C) 2002 Elsevier Science B.V. All rights reserved.