Gallium arsenide (GaAs)-based photoconductive switches for pulse generation and sampling applications in the nanosecond regime

The design is described of a set of optoelectronic switches having an interdigitated electrode structure and implemented with high-resistivity GaAs photoconductive substrates. A theoretical analysis is developed for determining the pulsed light ON-state resistance (peak conductance), OFF-state (dark) resistance, and the associated capacitances for the various designed gap geometries. Data are provided on the processing steps used in successfully fabricating a working set of switches based on the theoretical design. A test apparatus is used to make measurements of the pulsed light conductance of these devices having nominal gap spacings of 5, 10, 20 and 40 mu m.<
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