Analysis of the Performance of Gallium Arsenide Photoavalanche Switches
LAWRENCE LIVERMORE NATIONAL LAB CA
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This work investigates how the dielectric relaxation that occurs after optical absorption can raise the electrical field from below avalanche threshold to above threshold inside a simple GaAs photoconductor. The process of optically raising the electrical field above its initial value we call dynamic field enhancement. Trade-offs between optical intensity, doping, optical absorption depth, and sample thickness are discussed with respect to obtaining useful performance of a dynamically field enhanced photoavalanche switch. We trace the origin of various contributions to field enhancement and deduce certain bounds on the magnitude of the process. In this work, response time is not considered. From a one-dimensional analysis, we conclude that, in homogeneous photoconductors with ohmic contacts, dynamic field enhancement is limited at low fields to roughly a factor of two increase. We compare our analysis to one- and two-dimensional calculations obtained with computer codes based on a driftdiffusion model.
- Electrical and Electronic Equipment
- Electrooptical and Optoelectronic Devices
- Electricity and Magnetism