Функционализация развитой поверхности кремниевых наноструктур по данным синхротронных исследований

Semiconductor solid solutions draw considerable attention of modern science and technology. Such structures open prospects to gradually change electronic and optical characteristics of semiconductor materials. A particular task concerns Si1-xSnx solid solutions, which can allow to control optical properties in the near-IR region, as well as to adjust charge carriers’ generation, recombination and transfer processes on their basis. These alloys would allow to create new optoelectronic devices, e. g., lasers, and cost-efficient thermoelectric converters. However, the substantial difference of Si and Sn lattice constants (approximately 17 at%) and a low mutual solubility of the elements constrains the creation of homogenous Si-Sn structures. This limitation can be overcome in non-equilibrium conditions, е. g., by using molecular beam epitaxy (MBE). The aim of this work is the study of MBE-grown strained Si1-xSnx solid solutions’ electronic structure by means of non-destructive techniques of X-ray spectroscopy: XANES (X-ray Absorption NearEdge Structure) and USXES (Ultra-Soft X-ray Emission Spectroscopy); and to analyze the chemical bonds in the resulting materials with the XPS (X-ray photoelectron spectroscopy) technique. These methods are efficient for investigations of local electronic structure of near-surface thin layers, thanks to high sensitivity to local environment of atoms under study, and due to usage of synchrotron radiation sources allowing to achieve high radiation intensity and energy resolution. The results of this work allow to confirm the formation of Si0,92 solid solutions having a lower Sn0,08 band, than Si, and smoothed density of states due to presence of large tin atoms in the silicon lattice. It is observed that the formation of solid solutions is accompanied by changes of Si and Sn atoms’ bond energy. If the sample is covered by a 10 nm thick capping Si layer, this layer is characterized by a bulk-like single crystalline Si structure and negligible strain level. Therefore, the absence of notable elastic strain in the upper capping Si layer manifests the pseudomorphic nature of the em-