Doping of InSb thin films with lead Original Research Article

The incorporation of lead into polycrystalline InSb thin films is investigated. Several experimental methods are used to determine the distribution and solubility limit of lead in the InSb films. Considering the electrical neutrality of Pb in InSb films and difficulties in distinguishing between the lead incorporated into the lattice and lead in the metallic inclusions, the solubility of Pb in InSb is not determined in detail. The results show that the solubility should be well below 0.2 at.%, which is considerably smaller than that of about 0.5 at.% found in the earlier investigations. This behaviour of Pb is explained on the assumption that it substitutes in Pb–Pb pairs for the nearest-neighbour In–Sb pairs. The only clear manifestation of the presence of Pb in the InSb lattice is the weak localisation effect at temperatures below 7 K. The magnitude of the effect and the temperature range of its observation are appreciably higher than those found previously in InSb.