Voltage offsets in (Pb,La)(Zr,Ti)O_3 thin films

摘要

Cooling (Pb,La)(Zr,Ti)O_3 films from their pulsed laser deposition temperature in a reducing ambient yields a voltage offset in the polarization—voltage characteristics. Reversing the as-processed polarization at 120℃ nearly removes the offset. By reversing the polarization at room temperature and either heating the film at zero voltage or illuminating the film with UV light, the offset can be partially changed. All changes are recoverable using the same processes with opposite polarity polarization. This behavior is explained by a process-induced accumulation of oxygen vacancies at one interface, oxygen vacancy defect-dipole complexes throughout the film, and trapping of free electrons at the interface of positive polarization. Voltage offset and shift effects are not observed in films cooled in 1 atm of oxygen