Space-Charge-Limited Currents in Single Crystals of Cadmium Sulfide

Currents as high as 20 amperes per ${\mathrm{cm}}^2$ can be drawn through thin insulating crystals of CdS in the dark. A series of experiments demonstrate with a high degree of certainty that these are space-charge-limited currents—the solid state analog of space-charge-limited currents in a vacuum. This conclusion is contrary to a recently published interpretation of similar observations on CdS crystals by Böer and Kümmel.