Improved morphology of PbTe epilayers grown by LPE from supercooled growth solutions

Elimination if solvent inclusions and reduction of dislocation density in PbTe epilayers was achieved by LPE growth from supercooled solutions, rather than by equilibrium-cooled growth. Under supercooling growth conditions, the material deposition rate at growth initiation is higher, resulting in an increase in nucleation density as well as enhanced lateral growth of the initially formed nuclei. The fast lateral growth at the early stages of the epitaxial growth forms larger initial grains, which cover substrate areas where nucleation centers are not necessarily available. The larger initial grains coalesce to form a smooth epitaxy in less than 60 s from growth initiation. Under these conditions, the minimum nucleation density needed to achieve a smooth epilayer was found to be ∼1.7x10⁵/cm². As the epitaxial growth continues, the supercooling consitions disappear and further growth proceeds under equilibrium cooling conditions.