Numerical simulation studies with heterostructure of transition metal dichalcogenides*

Transition metal dichalcogenides (TMDs) are intriguing two-dimensional materials that have been intensively studied for almost two decades due to the attractive physical properties: controllable energy band gap which covers the visible and near-infrared wavelength range, strong light-matter interaction, strong spin-orbit coupling, direct bandgap with monolayer, and valleytronic properties. Although a monolayer has a drawback of low light absorption due to the thin physical structure, heterostructures of TMDs showing improved sensitivity of light are exploited in photonic devices. Large numbers of TMD heterostructure photodetectors have been demonstrated from zero-bandgap to wide-bandgap values over 3.1 eV. These studies are qualitatively explained by band alignment engineering but have not been intensively studied with thorough numerical simulations. In this presentation, we performed a variety of TMD material combination studies under finite element numerical simulation with COMSOL Multiphysics which elaborate how the transport properties behave in dark and photocurrent. Furthermore, we examined interesting results from the combination of a TMD heterostructure and a graphene structure.