Photonic interactions with surface semiconducting barrier discharges

In air at atmospheric pressure is necessary, atmospheric-pressure plasmas (APP) surface discharges are not often homogeneous nor simultaneously high in energy density. Based on silicon-on-insulator (SOI) technology, the semiconducting barrier discharge propagates uniformly at all times, never branching into streamers. This is in contrast to surface dielectric barrier discharges (SDBD), where quasi-uniformity is achievable only under certain conditions, with streamers propagating in closely-packed fashion. Moreover, unlike SDBD, the semiconducting barrier discharge maintains quasi-uniformity with both positive and negative voltage polarities. Our objective is to elucidate whether a photoelectric effect strongly couples the air plasma with an electron-hole plasma in the silicon. To create a surface discharge, we place a pin electrode in contact with the SOI barrier without a gas gap. Plasma was generated using nanosecond high-voltage pulses and characterized by fast imaging and current-voltage measurements. The pulse repetition frequency affects plasma extent, possibly due to memory effects associated with surface charge deposition and/or charge kinetics within the SOI material. The hypothesized photonic interaction was also imitated by directing external illumination at various wavelengths onto the surface. The plasma emission intensity and extent increase upon reaching a threshold for illumination intensity and depend on the illumination wavelength.