A first principle study of pressure‐induced properties of MoS2–graphene heterostructures

Abstract

AbstractWe examine the capabilities of the ab‐initio calculations within density functional theory (DFT) on the 2D monolayer MoS2, graphene, and Gr‐MoS2 heterostructure. The stability, elastic properties, acoustics, electronic and optical properties of the three hexagonal MoS2, graphene, and Gr‐MoS2 heterostructure is presented. The energy bandgap and both Total and partial density of states are calculated within the PBE functional and are enhanced by the HSE06 functional. Gr‐MoS2 hold an indirect bandgap (0.294 ev) while MoS2 is a direct bandgap (1.83 eV); moreover, graphene is used in its metal form in our calculations. The geometrically optimized relaxed structural parameters are (a = b = 3.308 Å, c = 11.961 Å), (a = b = 3.156 Å, c = 12.440 Å), and (a = b = 2.450 Å, c = 7.286 Å) for Gr‐MoS2, MoS2, and Gr, respectively. The energy bandgap of the three hexagonal crystals is induced in the pressure limit (0–40) GPa. Pressure give rise to bandgap in Gr, and does not affect the MoS2 bandgap significantly, whereas the minimal bandgap for Gr‐MoS2 changes drastically under pressure. The pressure‐dependent elastic moduli and related mechanical characteristics are reported. The optical properties are calculated throughout incident photon energies (0–40 eV). Most of the reported properties show a relative agreement with the cited literature. However, there are no experimental nor reliable theoretical results for the Gr‐MoS2 heterostructure, and to the best of the author's knowledge many of the results of Gr‐MoS2 are reported first in this work.