Copper-Doped Germanium as a Model for High-Resistivity Photoconductors

Abstract

In the electrical behavior of high-resistivity copper-doped germanium the nature of the electrodes plays an essential role. Three different types of space-charge contacts can be distinguished. For two types of contacts only primary photocurrents are observed, for the other both primary and secondary photocurrents. The secondary photocurrent is observed only in samples with the electrodes prepared in such a way that they show the space-charge-limited current. A simple theory on the magnitude of the secondary photo-current is confirmed experimentally. Also, some observations are given on the space-charge-limited current and some experiments which throw light on the mechanism of electrical breakdown in this material.