Multilayered Periodical Structures with Elastically Strained Gesisn Layers and Gesisn Nanoislands

This work deals with elastically strained GeSiSn films and GeSiSn islands. Kinetic diagram of GeSiSn growth at different lattice mismatches between GeSiSn and Si has been established. Multilayer periodic structures with pseudomorphic GeSiSn layers and GeSiSn island array have been obtained. The density of the islands in the GeSiSn layer reaches 1.8 ⋅ 1012 cm−2 at an average island size of 4 nm. Analysis of the rocking curves showed that the structures contain smooth heterointerfaces, and strong changes of composition and thickness from period to period have not been found. Photoluminescence has been demonstrated and calculation of band diagram in the model solid theory approach has been carried out. Luminescence for the sample with pseudomorphic Ge0.315Si0.65Sn0.035 layers in narrow range of 0.71—0.82 eV is observed with the maximum intensity near 0.78 eV corresponding to a 1.59 µm wavelength. Based on a band diagram calculation for Si/ Ge0.315Si0.65Sn0.035/Si heterocomposition, one can conclud that luminescence with a photon energy of 0.78 eV corresponds to interband transitions between the X−valley in the Si and the heavy hole subband in the Ge0.315Si0.65Sn0.035 layer.