Calcium modified lead titanate thin films for pyroelectric applications

Abstract

Calcium-modified lead titanate (PCT) thin film pyroelectric infrared (IR) detectors were fabricated on Pt(111)/SiO/sub 2//Si[100] substrates using a diol-based sol-gel process. The randomly oriented PCT thin film, which has not undergone the poling treatment, exhibits a relatively small dielectric constant 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 detectors was found to be the PCT(25), which exhibits a large voltage responsivity of 4533 (V/W) at 20 Hz and a specific detectivity (D*) of 6.45 /spl times/ 10/sup 7/ cmHz/sup 1/2//W at 100 Hz The results show that Pb/sub 1-x/Ca/sub x/TiO/sub 3/ thin film with x = 0.25 [PCT(25)] was most suitable for application to the pyroelectric thin film IR detector.