Changes in Conductivity resulting from Breakdown in Cadmium Sulphide Single Crystals

Abstract

For small applied fields the resistivity of a pure cadmium sulphide crystal is very high. For fields greater than a critical value, however, dielectric breakdown occurs and large currents flow. If the crystal is protected from destruction by a limiting resistor it is found on re-measurement at small fields, after the passage of a high current, that the conductivity and photosensitivity have been greatly increased. The increase in conductivity is greater, the larger the current passed through the crystal after the initial breakdown. This activating effect has been examined in detail, and it is shown that the changes which occur as a result of the passage of high currents take place largely in the bulk of the crystal.