The spectral dependence of the reflectance in the plasma-resonance frequency range was measured on the (00•1) cleavage faces of Bridgman-grown monocrystals of Sb2-xInxTe3, where x was between 0 and 0.41, that had been prepared from 5N-purity elements. The plasma-resonance frequency (and thus the concentration of holes) was determined from the spectral dependence of the reflectance. The dependence of the hole concentration upon the In content exhibited a monotonic decrease from 6.4 x 1025/m3 at x = 0 to 1025/m3 at x = 0.41. In order to account for the decrease in the hole concentration, a model was proposed which was based upon the assumption that the introduction of In atoms resulted in a decrease in the concentration of antisite defects and, at the same time, led to a change in the concentration of vacancies in the Te sub-lattice of Sb2Te3 crystals.

J.Horák, S.Karamazov, P.Lošták: Philosophical Magazine B, 1995, 72[6], 627-36