Asymmetric metal-ferroelectric-metal ͑MFM͒ structures were manufactured by sol-gel deposition of a lead zirconate-titanate ͑PZT with Zr/Ti ratio 65/35͒ film on Pt-coated Si, with a Au top electrode. The average remnant polarization of 9 C/cm 2 and the coercive field of 39 kV/cm were obtained from the hysteresis loop measurements. A detailed analysis of the polarization-electric field ( P -E), capacitance-voltage (C -V), and current-voltage (I -V) measurement results allowed us to estimate the near-electrode space-charge region thickness ͑roughly half of the film thickness at zero voltage͒, net doping concentration ͑around 10 18 cm Ϫ3 ), built-in potential ͑in the 0.4 -0.8 V range, depending on the injecting electrode͒, and dynamic dielectric constant ͑5.2͒. The current logarithm-voltage dependence for the field-enhanced Schottky emission obeys a ''1/4'' law. The spectral distribution of the short circuit current measured under continuous light illumination in the 290-800 nm range exhibits a cutoff wavelength at 370 nm and a maximum sensitivity at about 340 nm. The estimated band-gap energy of the PZT material is 3.35 eV. The MFM structure is discussed in terms of two back-to-back Schottky diodes with a ferroelectric material in between. It is concluded that the semiconductor properties of the films are not negligible and, in certain conditions, are dominating over the ferroelectric ones.

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