Direct formation of self-assembled quantum dots under tensile strain by heteroepitaxy of PbSe on PbTe (111)

Abstract

Direct growth of tensile-strained PbSe quantum dots by molecular beam epitaxy on 5.5% lattice mismatched PbTe (111) is investigated by atomic force microscopy and in situ reflection high energy electron diffraction. After wetting layer formation, two types of PbSe islands are formed distinguishable in size and ordering behavior. All islands exhibit a well defined pyramidal shape with triangular base and steep (100) side facets. In addition, the dots exhibit a remarkably narrow size distribution with a relative variation of height and width as low as ±7%.