Optoelectronic switch performance in double heterostructure-emitter bipolar transistor

The behavior of optoelectronic switch is examined in GaAs-AlGaAs double het erostructure-emitter bipolar transistors with exposed p(+)-GaAs surface, n- GaAs surface, and N-AlGaAs passivated surface. Due to the symmetric structu re with respect to the base layer, the devices operate as bi-directional sw itches which result from the avalanche multiplication and transistor action in the transport mechanism. The devices also show optical functions relate d to the potential barrier height and breakdown voltage controllable by inc ident light. Moreover, the device with AlGaAs passivated surface exhibits a highest optical sensitivity and a lowest holding power among the studied d evices because of the effective decrease of the surface recombination curre nt. (C) 2001 Elsevier Science Ltd. All rights reserved.