Results of experimental investigation of the non-steady-state photoelectromotive-force effect in ferroelectric photorefractive Sn<sub>2</sub>P<sub>2</sub>S<sub>6</sub> crystals at a wavelength of 633 nm are reported. The dominating photoconductivity proved to be of the <i>p</i> type, with a diffusion length of photocarriers of ∼1 μm. This characteristic length proved to be shorter than the Debye-screening length evaluated as ∼3 μm in this crystal. The millisecond characteristic time of the space-charge grating formation was determined by the photoconductivity-relaxation time, which was found to be a little bit longer than the dielectric-relaxation time. Both of them dropped sublinearly with increasing average light intensity in the investigated region I<sub>0</sub>≃0.5–0.01 mW/mm<sup>2</sup>.
© 2000 Optical Society of America
Ismael Seres, Serguei Stepanov, Svetlana Mansurova, and Alexander Grabar, "Non-steady-state photoelectromotive force effect in photorefractive Sn2P2S6 crystals," J. Opt. Soc. Am. B 17, 1986-1991 (2000)