The project is a part of the vigorously growing area ofsemiconducting two-dimensional crystals,
which was initiated by a discovery of graphene. So far, the interest of researchers have been focused
mainly on the semiconducting layered materials, such as transition metal dichalcogenides (e.g. MoS2,
WS2, MoSe2, WSe2 and MoTe2) or metal monochalcogenides (e.g. InSe, Gase, GaS and GaTe), which
properties vary extremely in the transition from the bulk crystal to a single atomic layer. In particular,
the character of their band gaps changes from the indirect to direct one.
In this project are proposed research of excitonic complexes in two types of samples: (i) high
quality thin layers of different members of aforementioned materials obtained by their encapsulation in
hexagonal BN, (ii) artificially stacked van der Waals (vdW) heterostructures of at least two different
layered materials, e.g. WSe2 and InSe, where a new complexes of excitons may be apparent. Therefore,
the materials may have practical applications in the field of optoelectronics and photovoltaics, as their
band gaps cover broad electromagnetic range from UV to NIR. Within the project, there are planned
investigation using various spectroscopic techniques, such as photoluminescence, reflectance contrast
and Raman scattering, and under different conditions, i.e. as a function of temperature and in external
magnetic fields.
The aim of the project is broaden the knowledge of the properties of the different excitonic
complexes formed in thin layers of studied materials. Excitons as associated with the excitation of
carriers in materials are very interesting complex from fundamental and potential applications points of
view. This study will enable a better understanding of formation of excitons and coupling between thin
layers in vdW heterostructures.