van der Waals graphene/MoS₂ heterostructures: tuning the electronic properties and Schottky barrier by applying a biaxial strain

Abstract

The interlayer distance and biaxial strain affect the electronic properties and contact properties of graphene/MoS2 heterostructures.

All‐Gas‐Phase Synthesis of Heterolayered Two‐Dimensional Nanohybrids Decorated with Metallic Nanocatalysts for Water Splitting

“…Due to van der Waals interactions between the basal plane of graphene and Se or S atoms, the structure of the graphene model in binary systems was bent toward the surface of the WSe 2 and MoS 2 models. [ 39 ] On the other hand, due to the interaction with both WSe 2 and MoS 2 models, the structure of the graphene model in the ternary system was flat and interstratified between the WSe 2 and MoS 2 models. As shown in Figure 5b, an electron density distribution analysis was performed to gain additional insight into the interaction between the constituent 2D materials.…”

The structure and electronic properties of the MoSe2/PtS2 van der Waals heterostructure

“…Then, the MoSe 2 /PtS 2 van der Waals heterostructure is constructed by perpendicularly stacking one unit cell of monolayer PtS 2 onto one unit cell of the MoSe 2 monolayer along the c direction. The optimization of the MoSe 2 /PtS 2 van der Waals heterostructure is realized by the two-step method 65 (see the ESI†). Here, the lattice mismatch is defined as where a MoSe 2 and a PtS 2 represent the lattice constant of monolayers MoSe 2 and PtS 2 , respectively.…”

“…3(a) shows the evolution of binding energy and band gap as a function of the interlayer distance. As mentioned above, the binding energy E b is fitted by the well-known Buckingham potential equation, 65 where a , b , and c are fitting parameters of −2.337 eV, 0.107 Å, and −42.098 eV, respectively. The negative binding energy, E b , can be obtained and when the interlayer distance increases from 2.0 to 4.0 Å, the evolution of E b follows the typical Lennard-Jones-type potential, 82 which exhibits the same trend as those of other heterostructures such as GeSe/PtS 2 , 71 XPtY-Graphene 83 and so on.…”

“…To determine whether the contact between monolayer MoSe 2 and PtS 2 monolayer is Ohmic contact or not, the barrier height is calculated. Herein, the n-type (p-type) Schottky barrier height is defined as h SB,N = E CBM − E F ( h SB,P = E F − E VBM ), 65 where E CBM , E VBM , and E F are the conduction band minimum, valence band maximum, and Fermi level, respectively. The calculated h SB,N and h SB,P values are 0.652 eV and 0.999 eV for the MoSe 2 /PtS 2 heterostructure under +7% biaxial tensible strain, respectively.…”

“…3(a) shows the evolution of binding energy and band gap as a function of the interlayer distance. As mentioned above, the binding energy E b is fitted by the well-known Buckingham potential equation, 65…”