Electron-Hole-Transport in Photorefractive media,
YALE UNIV NEW HAVEN CT DEPT OF APPLIED PHYSICS
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Recently, electron-hole transport in photorefractive media has received much interest. Many observations which cannot be accounted for by simple single-carrier single-level transport can be explained by electron-hole transport. This summary describes electron-hole transport by two different models and describes a regime in which both models give similar results. For the single-level electron-hole-transport model considered, one species of traps exists in the band gap, and charge transfer occurs by both electron and hole transport. For the two-level electron-hole-transport model, two species of traps exist in the band gap, and charge transfer occurs by electron transport for the species closest to the conduction band and by hole transport for the species closest to the valence band. For most regimes, the two models give significantly different results. Saturation space-charge fields depend on the model used for the single-level model, the field depends on the relevant rate constants, but for the two-level model, it depends on the relevant limiting space-charge fields. The number of time constants depends on the model used the single-level model yields one time constant, whereas the two-level model yields two. And only the two-level electron-hole-transport model allows the presence of complementary gratings.
- Nuclear Physics and Elementary Particle Physics