Direct proof of the conduction type in semi-insulating thin films

It is shown that measurements of thermally stimulated relaxation currents (thermally stimulated polarization (TSP) and thermally stimulated depolarization (TSD)) can be used to determine directly the conduction type in semi-insulating thin films. Choosing an appropriate temperature range the described method should be applicable to all nonmetals. Experiments with amorphous As2Te3 layers confirm p-type conduction in this material. Moreover the obtained results represent a convincing experimental evidence for a semiconductor in the relaxation regime.