Anisotropy of the Electron and Hole Drift Mobility inKNbO3andBaTiO3

Abstract

We determine the anisotropy of the mobility of photoexcited charge carriers in single crystals of KNbO 3 and BaTiO 3 by means of a purely optical method. In orthorhombic KNbO 3 the mobility anisotropy is measured for both electrons and holes giving m a ͞m c 1.05 6 0.06, m b ͞m c 2.9 6 0.3 for holes and m a ͞m c 1.15 6 0.09, m b ͞m c 1.9 6 0.2 for electrons. In BaTiO 3 we find for holes m a ͞m c 19.6 6 0.6. Our experiment also demonstrates that the acoustic phonon contribution to the dielectric permittivity is substantially different for spatially modulated electric fields as compared to the homogeneous case.

Dynamic charge-carrier-mobility-mediated holography in thin layers of photoconducting polymers

“…Similar systems, previously studied show interesting properties such as an efficient energy transfer in the two-beam coupling experiments 5,6 with extremely high exponential gain coefficient ⌫ϭ3700 cm Ϫ1 , and other properties useful in the whole range of real-time holography. 7,8 The present study was inspired by the recent work of Biaggio et al [9][10][11] which proposed the use of the holographic method for the contact-less optical characterization of charge transport in the bulk photorefractive crystals. The influence of charge mobility on the transient bahavior of refractive index gratings in photorefractive polymers was also studied by Malliaras and co-workers.…”

Charge Carrier Photoexcitation and Two-Wave Mixing in Dichroic Materials

“…We have performed photoconduction experiments using a holographic technique similar to the one in Ref. [17]. The time constant for photoerasure of a space-charge grating under the influence of an erasing beam polarized either along the b-or c-crystal axis direction was measured.…”

L'effet photoréfractif

“…La mobilité est fortement anisotrope [161]. De même, la longueur de diffusion dépend de l'orientation du vecteur réseau.…”