HIGH-TEMPERATURE BEHAVIOR OF IMPURITIES AND DIMENSIONALITY OF THE CHARGE-TRANSPORT IN UNINTENTIONALLY AND TIN-DOPED INDIUM SELENIDE

A systematic study of the electron transport and shallow impurity dist ribution in indium selenide above room temperature or after an anneali ng process is reported by means of far-infrared-absorption and Hall-ef fect measurements. Evidences are found for the existence of a large co ncentration of deep levels (10(12)-10(13) cm-2), related to impurities adsorbed to stacking faults in this material. Above room temperature impurities can migrate from those defect zones and then become shallow in the bulk. The subsequent large increase of 3D electrons can change the dimensionality of the electron transport, which in most cases was 2D. The temperature dependence of the resistivity parallel to the c a xis can be explained by the observed increase of the 3D electron conce ntration, whose motion across the layers is limited by stacking-fault- related potential barriers. The observed macroscopic resistivity is th us determined by tunneling through those barriers.