Behaviour of polycrystalline selenium layers at high current densities

The paper describes measurements of the current-voltage characteristic of polycrystalline selenium layers at high current density values. At first it is shown that the composition of a counter electrode (Sn, Cd, CdSn) does not influence the character of the dependence of the current density vs. voltage. When measuring the influence of thickness of polycrystalline layers of selenium on the behaviour of the current-voltage characteristic, three regions on the current-voltage characteristic were observed. For the lowest voltage the current density isjU/d and so Ohm's law can be used. For higher voltagejU^1.35/d^1.175. For the highest voltage the relationjU²/d^1.5 was found. It will probably be possible to explain the results of measurements by means of the existence of space-charge-limited current.I should like to express my sincere gratitude to the specialists from the Institute of the Rectifiers Research at B~chovice for their very careful preparation of the samples, which made possible to carry out really reproducible and comparable measurements.