Pressure-Induced Charge Transfer Doping of Monolayer Graphene/MoS<inf>2</inf>Heterostructure

Abstract

A combined theoretical and experimental investigation on the effects of hydrostatic pressure on the vertically stacked heterostructure composed of monolayer graphene and monolayer 2H-MoS was reported. A diamond anvil cell (DAC) with a soft neon pressure medium in a sample chamber made of a Re gasket was used to apply a hydrostatic pressure uniformly across the stacked structure. The electronic structure calculation confirms a linear shift in Dirac point of grapheme with respect to Fermi level under hydrostatic pressure. This shift in Dirac point was quantified in terms of doping concentration as a function of hydrostatic pressure. The doping concentration exhibits an exponentially increasing dependence upon pressure, providing a route to an unprecedented tunability. Analysis of the intensity ratio of the 2D and G band demonstrates strong pressure dependence and confirms the theoretically predicted heavy p-type doping in graphene. Pressure-dependent Raman studies and theoretical insights show that applying hydrostatic pressure strongly influences the charge transfer doping between graphene and MoS , making pressure a prominent factor in tuning the doping concentration of graphene and potentially other van der Waals solids. 2 2