Time-resolved impact ionization in ZnSe high-voltage switches

Fast electrical streamer and glow avalanches in ZnSe semiconductors are investigated, for applications in fast spontaneous or triggered switches. We present time-resolved observations of these self-sustained, impact ionization events in bulk polycrystalline ZnSe at room temperature. Under high voltages (~20 kV) short-current pulse (~3 ns) electrical excitation, the 1 ns risetime current pulses cause the emission of the bandgap radiation, which in turn is used to characterize the role of the plasma during the switching interval. Using a picosecond resolution streak camera, plasma streamers were recorded, in undoped ZnSe, and a uniform glow was observed in n-doped samples for the duration of the 3 ns, 1 kA current pulse. This paper concerns the behavior of the avalanche breakdown mechanism, which is relevant for applications in high energy switches, and we will discuss the possibility of using the avalanche process to pump high-power light-emitting semiconductor devices