Pyroelectric properties of La-modified lead titanate thin film detectors

High-performance pyroelectric infrared (IR) detectors have been fabricated without the back side etching process using La-modified lead titanate (PLT) thin films. PLT thin films were deposited on (111)-oriented Pt thin film o n SiO2/Si(100) substrates by a diol-based sol-gel process. The randomly ori ented PLT thin film exhibits a relatively small dielectric constant and a l arge pyroelectric coefficient without poling treatment. The pyroelectric ch aracteristics of point detectors with various La contents as a function of modulation frequency are compared. It was found that the PLT(10) detector h as a large voltage responsivity of 3330 (V/W) at 20 Hz. The specific detect ivity (D*) at 100 Hz is 6.2 x 10(7) cmHz(1/2)/W. The results showed that Pb 1-xLaxTi1-x/4O3 thin film with x = 0.10 [PLT(10)] was most suitable for use as a pyroelectric IR detector.