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

Calcium-modified lead titanate (PCT) thin film pyroelectric infrared (IR) d etectors were fabricated on Pt(111)/SiO2/Si(100) substrates using a diol-ba sed sol-gel process. The randomly oriented PCT thin film, which has not und ergone the poling treatment, exhibits a relatively small dielectric constan t and a large pyroelectric coefficient. The pyroelectric properties of PCT thin film point detectors with various Ca contents on modulation frequency are measured and compared. The optimized composition of PCT thin film IR de tectors was found to be the PCT(25), which exhibits a large voltage respons ivity of 4533 (V/W) at 20 Hz and a specific detectivity (D*) of 6.45 x 10(7 ) cmHz(1/2)/W at 100 I-It. The results show that Pb1-xCaxTiO3 thin film wit h x = 0.25 [PCT(25)] was most suitable for application to the pyroelectric thin film IR detector.