Effect of surface conduction in the semiconductor electrode on the distribution of the gas-discharge current

Abstract

A planar gas-discharge structure, in which one of the electrodes is a high-resistivity semiconductor capable of providing stable uniform distribution of the current and the gas-discharge’s light emission within the entire volume of the gas-discharge gap, is studied. It is established that the effect of the semiconductor electrode on the distribution of the steady-state current in the gas-discharge gap is associated with the conductivity of the electrode’s surface layer, whereas the resistance of the semiconductor bulk defines only the load resistance. It is experimentally shown that local metallization of the semiconductor surface results in current pinching in the metallized areas. It is concluded that the basic physical effect that limits the probability of current pinching and provides stable discharge is associated with the electric field orthogonal to the current pinch at the point of its contact with the semiconductor. A qualitative analysis of this effect is presented. The obvious condition of smallness of this field compared to the longitudinal field in the pinch allows two types of pinching: one corresponds to the formation of a solitary pinch at a fairly high conductivity of the semiconductor’s surface layer, whereas the other corresponds to the formation of a large number of pinches, almost totally covering the surface of the electrode, at a low surface conductivity.