Simultaneous electron/hole transport in photorefractive materials

The steady‐state space‐charge field and the response time of a photorefractive material illuminated with a sinusoidal interference pattern are derived for two models in which both electron and hole transport are important. In the first model in which electrons and holes are produced from a single set of recombination centers, the sign of the steady‐state space‐charge field depends on the relative value of the conductivities and/or absorption coefficients of the electrons and holes, and a single response time proportional to irradiance is obtained. In the second model in which electrons are photoionized from one set of recombination centers and holes from another, the sign of the space‐charge field depends on the relative concentrations of the empty hole and electron traps, and two time constants, each inversely proportional to irradiance, are obtained.

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