A Bulk Optically Controlled Semiconductor Switch

Turn‐on and turn‐off of bulk semiconductor switches, based on excitation and quenching of photoconductivity, respectively, have been demonstrated with copper‐doped II‐VI semiconductor crystals. The increase of the conductivity (turn‐on) was realized with a xenon flash‐lamp pulse of 15‐μs duration. A reduction of the conductivity (turn‐off) was obtained by irradiating the samples with IR light using an 8‐ns Nd:YAG laser pulse (YAG denotes yttrium aluminum garnet). For turn‐on in CdS:Cu the conductivity follows the xenon flash excitation. The turn‐off time constant was 250 ns. ZnS and ZnSe crystals showed a slower response. A memory effect for the IR light was observed