High current photoconductive semiconductor switches

It is shown that Si photoconductive semiconductor switches (PCSSs) can be used to switch high voltages (up to 123 kV), high fields (up to 82 kV/cm) and high currents (2.8 kA). The ability of the samples to withstand this type of high-voltage, high-current switching depends on the way in which the current penetrates the semiconductor. The appropriate use of water or contacts greatly improves the switching capability. It is also shown that the wafers can support large currents (4.0 kA for GaAs and 2.8 kA for Si) and large linear current densities (3.2 kA/cm for GaAs and 1.4 kA/cm for Si). For GaAs, this linear current density corresponds to about 1 MA/cm/sup 2/, given a penetration depth of about 10/sup -3/ cm. It is determined that the lock-on phenomenon can be triggered with light of varying photon energy to reach a lock-on field that is both impurity-concentration and sample-temperature dependent.<
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