Pyroelectric properties of sol-gel derived (Pb,Mg)TiO3 thin film detectors

High-performance pyroelectric infrared (IR) detectors have been fabricated without the back side etching process using Mg-modified lead titanate (Pb1-xMgxTiO3) thin films. PMT thin films were deposited on (111)-oriented Pt thin film on SiO2/Si(100) substrates by a diol-based sol-gel process. The randomly oriented PMT thin film exhibits a relatively small dielectric constant and a large pyroelectric coefficient without poling treatment. The pyroelectric characteristics of point detectors with various Mg contents as a function of modulation frequency are compared. It was found that the PMT(6) thin film detector has a large voltage responsivity of 5280 (V/W) at 20 Hz. The specific detectivity (D*) at 100 Hz is 5.12x10(7) cmHz(1/2)/W. The results showed that Pb1-xMgxTiO3 thin film with x=0.06 [PMT(6)] was most suitable for use as a pyroelectric IR detector.