ELECTROABSORPTION FIELD IMAGING BETWEEN COPLANAR METAL CONTACTS ON SEMIINSULATING SEMICONDUCTOR EPILAYERS

We use excitonic electroabsorption field imaging to study the electric field distribution between coplanar gold Schottky contacts on semi-in sulating photorefractive AlGaAs epilayers. The field imaging shows con sistently large localized enhancements of the electric field adjacent to the anode, followed by a region of reduced held. Complex behavior o ccurs at the cathode, with high-field regions extending far from the c ontact. These inhomogeneous near-contact field profiles are determined by the superposition of both diffused and drifted charge which affect the performance of many optoelectronic devices that use planar contac ts or striplines on semi-insulating substrates. (C) 1996 American Inst itute of Physics.