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 on 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 µ C/cm2 and the coercive field of 70 kV/cm. The responsivity and detectivity of the thin film infrared sensor are 700 V/W and 6×108 cm√ Hz/W at 10 Hz, respectively, without any poling treatment.