Optically controlled polarization in highly oriented ferroelectric thin films

The out-of-plane and in-plane polarization of (Pb_0.6Li_0.2Bi_0.2)(Zr_0.2Ti_0.8)O₃(PLBZT) thin film has studied in the dark and under illumination of a weak light source of a comparable bandgap. A highly oriented PLBZT thin film was grown on LaNiO₃ (LNO)/LaAlO₃(LAO) substrate by pulsed laser deposition system which illustrates well-saturated polarization and its significant enhancement under illumination of light. We have employed two configurations for polarization characterization; first deals with out of plane polarization with single capacitor under investigation, whereas second demonstrates the two capacitors connected in series via the bottom electrode. Two different configurations were illuminated using different energy sourcesand their effects were studied. The latter configuration shows a significant change in polarization under illumination of light that may provide an extra degree of freedom for device miniaturization. The polarization was also tested using positive-up & negative-down (PUND) measurements which confirm robust polarization and their switching under illumination.