Space-charge-induced optoelectronic switching in IIa diamond

Experimental results are presented concerning the effect of contacts on the performance of high-voltage optoelectronic switching in insulating diamond. For high bias voltages and low intensity 222-nm, ≊7-ns pulse illumination near the cathode, the switched voltage pulse splits into two peaks. The first peak corresponds to the high-speed photoconductive response of the diamond, while the second peak (which can be delayed up to ≊200 ns later) is attributed to space-charge-induced switching in the vicinity of the cathode.