High Electric Fields in Cadmium Sulfide: Field-Effect Constriction of Current Flow and Dielectric Breakdown

Field-effect measurements have been employed to study constriction of current flow in very thin single crystals of conducting CdS. With an electrolyte field electrode and crystals having about 1 ohm-cm resistivity, it has been possible to obtain complete pinch-off of current flow through the crystal by applying voltage to the field electrode. The technique used is evaluated quantitatively and is found to be a satisfactory method for obtaining high electric fields of known magnitude in CdS. Dielectric breakdown occurs when sufficiently high voltage is applied to the field electrode. The breakdown field strength was found to be 1.8×${10}^6$ v/cm at 25°C.