A complete set of charge-transport parameters of photorefractive cerium-doped strontium-barium niobate crystals is determined: the concentrations of filled and empty traps, the photon-absorption cross section, the quantum efficiency for excitation of an electron upon absorption of a photon, the recombination coefficient, and the charge-carrier mobility. These parameters are obtained evaluating optical absorption, conductivity, non-steady-state photocurrents, neutron-activation analysis, and x-ray photoelectron spectra. The effective absorption radius of the filled electron traps is small and the effective trapping radius is large compared with the ionic radii. Before recombination with deep levels the excited electrons are trapped several times by shallow levels. A detailed description of the charge transport is obtained, and the properties of optimized crystals are deduced.
© 1998 Optical Society of America
K. Buse, A. Gerwens, S. Wevering, and E. Krätzig, "Charge-transport parameters of photorefractive strontium-barium niobate crystals doped with cerium," J. Opt. Soc. Am. B 15, 1674-1677 (1998)