HgSe:Fe quantum dots: growth and characterization

Mercury selenide and its ternary and quaternary modifications in the form Hg(A,B)Se with A, B magnetic ions, provide an interesting semiconductor family featuring different kinds of correlation effects. These effects manifest themselves already in three-dimensional, quasi-two-dimensional, and quasi-one-dimensional structures. We have succeeded now in fabricating HgSe:Fe quantum dots using three different growing procedures based on molecular beam epitaxy: (a) Stranski–Krastanov growth; (b) thermally activated surface reorganization; (c) pit filling. The special feature of the HgSe:Fe dots is the intrinsic population of the dot states by electrons, where a large amount of about 50–500 electrons form a many-electron system within a single dot. The formation of the dots was controlled in situ by RHEED. The morphology of the resulting structures was characterized by AFM. Subsequently, the electronic properties of the dots were investigated by megagauss magneto spectroscopy, indicating the presence of strong correlation effects as manifested in a 50% increase of the cyclotron mass in respect to that of structures with a higher dimensionality.