Barrier photovoltaic effects in PZT ferroelectric thin films

The photoelectric characteristics (independent of ferroelectric polarizatio n) of metal-ferroelectric-metal thin film structures upon exposure to radia tion in different ranges of mercury arc lamp spectrum are studied for the P b(Zr0.52Ti0.48)O-3 (PZT) ferroelectrics. The PZT films on platinized silico n substrates were prepared by the sol-gel technique. The relaxations of the short-circuit current and the open-circuit voltage are investigated at dif ferent intensities of light with wavelengths in the range 300-1200 nm. It i s found that the open-circuit voltage returns to its original value after t he cessation of light exposure and a short-term holding of structures in th e short-circuited state. The factors responsible for the photocurrent and t he photoemf are analyzed, and the conclusion is made that they are predomin antly contributed by the barrier photovoltaic effects associated with the p resence of the p-n junction in the bulk of films and the Schottky barrier i n the film region adjacent to the lower platinum electrode. (C) 2000 MAIK " Nauka/Interperiodica".