MICROSTRUCTURES AND ELECTRICAL-PROPERTIES OF (PB,LA)TIO3 THIN-FILMS GROWN ON THE PT ELECTRODES WITH A PERCOLATING NETWORK STRUCTURE

We have investigated the microstructures and electrical properties of Pb0.95La0.05TiO3 (PLT) thin films deposited an the (100)-oriented Pt/(100)MgO substrates by rf magnetron sputtering and have fabricated a thin film infrared sensor. The (100)-oriented Pt film is formed via a coalescence of Pt islands and the Pt layer goes through a transition from nonconducting islands to a conductive percolating network as the Pt deposition time increases. The highly c-axis oriented PLT thin film has been successfully grown on the Pt bottom electrode with a network structure. The PLT thin film on the interconnected percolating Pt network exhibits a well saturated ferroelectric hysteresis loop with the remanent polarization of 1.6 mu C/cm(2) and the coercive field of 70 kV/cm. The responsivity and detectivity of the thin film infrared sensor are 700 V/W and 6 x 10(8) cm root Hz/W at 10 Hz, respectively, without any poling treatment.