Doping of InSb thin films with lead

The incorporation of lead into polycrystalline InSb thin films is investiga ted. Several experimental methods are used to determine the distribution an d solubility limit of lead in the InSb films. Considering the electrical ne utrality of Pb in InSb films and difficulties in distinguishing between the lead incorporated into the lattice and lead in the metallic inclusions, th e solubility of Pb in InSb is not determined in detail. The results show th at the solubility should be well below 0.2 at.%, which is considerably smal ler than that of about 0.5 at.% found in the earlier investigations. This b ehaviour of Pb is explained on the assumption that it substitutes in Pb-Pb pairs for the nearest-neighbour Ln-Sb pairs. The only clear manifestation o f 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 ra nge of its observation are appreciably higher than those found previously i n InSb. (C) 2000 Elsevier Science Ltd. All rights reserved.