We show how phase separation, in the form of a redistribution of impurities (dopants in a semiconductor), can occur at impurity concentrations that are more than one order of magnitude lower than hitherto observed. This phenomenon results from the balance between long-range electrostatic repulsion and the elastic attraction of the dopants, which deforms the anisotropic host lattice. We observed such a phase separation for Ag in (Cd, Hg)Te at Ag concentrations < 0.02 at. %. This also leads to the formation of a thermodynamically (as opposed to kinetically) stable p-n junction in the 2-phase region. Searching for phase separation at such low concentrations requires highly sensitive analyses, here made possible because of the difference in conductivity type between the phases.
ASJC Scopus subject areas
- Physics and Astronomy(all)