Effect on Schottky Barrier of Graphene/WS₂ Heterostructure With Vertical Electric Field and Biaxial Strain

Abstract

Graphene has been widely used in many applications, such as sensors, fieldeffect transistors, and integrated circuits due to its high strength and excellent electrical and thermal conductivity. Its lack of a band gap, however, means that applications in some fields are limited. In this paper, using first principles calculations based on the density functional theory method, the electronic properties of graphene/WS 2 heterostructures under electric field and in-plane biaxial strain are investigated. It is found that the two materials are subject to weak van der Waals forces after stacking. The band gap of WS 2 in the graphene/WS 2 heterostructure is reduced by 0.57 eV compared to the intrinsic WS 2 band gap. An n-type Schottky contact with a barrier height of 0.22 eV is formed. In addition, an n-type to p-type Schottky contact transition can be achieved by increasing the applied vertical electric field on the graphene/WS 2 heterostructure. The variation of the barrier heights ϕ Bn and ϕ Bp of the graphene/WS 2 heterojunction with strain is sensitive. However, plane strain can only change the height of the Schottky barrier; the Schottky contact cannot change from n-type to p-type with in-plane biaxial strain. The results suggest that there is a potential application of graphene/ WS 2 heterostructures in Schottky devices.

Tunable Electronic Properties and Potential Applications of BSe/XS2 (X=Mo, W) van der Waals Heterostructures

“…First, the E b for the MoS 2 (WS 2 )/BSe heterostructures is −217.20 (−295.00) meV, which is far less than that of the prepared graphene/WS 2 compound (−31.95 meV), [ 36 ] indicating a promising prospect to synthesis the XS 2 /BSe heterostructures experimentally. Next, the equilibrium distances of the MoS 2 /BSe, and WS 2 /BSe heterostructures are measured as 3.25 and 3.20 Å, respectively, which are very close to that of other existent TMDs‐based vdW heterostructures, such as graphene/WS 2 (3.32 Å), [ 36 ] and graphene/MoS 2 (3.40 Å). [ 37 ] This indicates the possibility of the existence of XS 2 /BSe vdW heterostructures.…”

Development of WS2/MXene (Ti3C2T x ) nanohybrid based multi-functional textronic sensor for non-invasive personal healthcare monitoring

“…These layered materials show a decrease in interlayer spacing when external pressure is applied, reducing the contact resistance amongst the nanoflakes, thereby enabling interlayer electron tunneling. The resistance created due to the formation of a heterojunction at the interface decreases with applied pressure due to SBH lowering (Φ' SB ) [52]. Figure 6 shows in graphical form the effect of external stimuli (pressure, strain) on the TMD/MXene layers and the tunneling phenomena that occur.…”

First Principle Study for Optical Properties of TMDCs/Graphene Heterostructures

“…Φ Bp = 0.65eV for MoSe 2 /Gr, Φ Bn = 0.39eV and Φ Bp = 1.13eV for WS 2 /Gr, and Φ Bn = 1.00eV and Φ Bp = 0.61eV for WSe 2 /Gr, respectively. Therefore, MoS 2 /Gr, MoSe 2 /Gr, WS 2 /Gr and WSe 2 /Gr are the n-type, p-type, n-type and p-type Schottky contacts, respectively [47,49,51].…”

“…The MX 2 /Gr are the type-I van der Waals heterostructures. The electronic properties of MoS 2 /Gr [33,[42][43][44][45], MoSe 2 /Gr [28,[46][47][48], WS 2 /Gr [29,49] and WSe 2 /Gr [50][51][52] have been revealed that MX 2 /Gr van der Waals heterostructures are favourable for optoelectronic applications and field-effect transistors. In this paper, we theoretically investigate the optical properties of MX 2 /Gr (M=Mo,W; X=S,Se) heterostructures.…”