It was shown that Hall effect data, determined as a function of the magnetic field at 77K, permitted the identification of extended defects and the evaluation of their parameters. Three different groups of samples were identified. Some exhibited a classical dependence upon the magnetic field. strength; with 2 plateaux in weak and strong fields and a transition which conformed to the theoretical value of the Hall factor for n-type material. This was true of the most perfect crystals. The distinctive feature of the second group was a monotonic decrease in the field dependence; which reached saturation only in very high fields. This was attributed to the presence of a second set of electrons which appeared when the constituent dislocation density on the sub-grain boundaries exceeded (at a certain misorientation across the boundary) a critical level which corresponded to the appearance of a percolation level. In the case of the third group, a minimum appeared between the plateaux. This was related to the effect of isolated inhomogeneities with a conductivity that was higher than the conductivity of the surrounding medium. This behavior was attributed to the presence of Te-rich precipitates.

N.N.Berchenko, J.S.Budzhak, K.R.Kurbanov, G.Sasvári: Semiconductor Science and Technology, 1993, 8[1], S225-8