Dr. Saeideh Edalati-Boostan – Theoretical and experimental study of optical properties of 2D material heterostructures

As light-based technologies have become indispensable in our modern world, demand for high-performing novel optical materials is growing and optimization of optical devices with respect to energy efficiency and cost effectiveness receives much attention. Low-dimensional materials feature unique advantages over their bulk counterparts and are expected to enable next-generation innovative technologies. Particularly, the opportunity of vertically stacking 2D materials offers vast possibilities of heterostructuring and band-gap engineering. Here, a joint theoretical and experimental study of optical properties of the (yet unexplored) MoSe2/MoTe2 and WSe2/MoTe2 monolayer (ML) heterostructures (HS) will be conducted. In this way the understanding of this material class and their possible applications will be demonstrated by investigating whether/how- Type-II HS of MoSe2/MoTe2 retains the direct band gap of their corresponding MLs and is a promising candidate for photovoltaic devices and detectors due to the presence of interlayer (or indirect) excitons;- Type-I HS of WSe2/MoTe2 is an ideal structure to be applied in low-threshold diode lasers due to the presence of intralayer (or direct) excitons;- Heterostructuring deteriorates the optical properties of MLs;- Lattice mismatch and substrate significantly affect the optical properties of HS.