PHOTOINDUCED POLING OF LEAD TITANATE ZIRCONATE THIN-FILMS

The influence of ultraviolet (UV) illumination on piezoelectric proper ties is investigated in lead zirconate titanate (PZT) thin films. It i s found that the poling procedure is more effective when the film is e xposed to a broadband UV light in the presence of a high electric fiel d. Piezoelectric coefficients are increased and aging rates are decrea sed as compared to poling in dark conditions. Both an internal bias fi eld and a polarization offset are observed in the piezoelectric hyster esis loops. The mechanism of the photoinduced poling effect in PZT fil ms is probably due to electron trapping near the film-electrode interf ace. (C) 1997 American Institute of Physics. [S0003-6951(97)00541-X].