The isolation of single-atomic layer graphene has led to a surge of interest in other layered crystals with strong in-plane bonds and weak, van der Waals-like, interlayer coupling. Here we research new properties of two-dimensional materials extracted from their layered bulk crystals. We published work on MoS₂, MoSe₂, WSe₂, WS₂, CrBr₃, GaSe, GaTe, InSe, MnPSe3, NiPS3, ZrSe2, HfSe2, GaS, hBN, as well as heterostructures and nano-photonic structures made from some of these materials.
In their bulk form layered materials may vary from insulators to semiconductors, from metals to superconductors, and exhibit magnetic and topological insulator properties. We obtain two-dimensional (2D) films by mechanical exfoliation from such layered crystals, often referred to as van der Waals crystals to describe the weak forces holding their atomic planes together.
The properties of few-atomic-layer 2D films may differ from the bulk quite dramatically. For example, some indirect band-gap semiconductors turn to direct band-gap ones and become optically active. Our recent effort is on development of hybrid photonic devices comprising these 2D films and artificially built van der Waals heterostructures consisting of atomically thin layers of various materials. We are also actively exploring how these layered materials in their thin-film can be used in nano-photonics.