Tunable band gap of MoS2-SiC van der Waals heterostructures under normal strain and an external electric field

Abstract

The structure and electronic properties of the MoS2/SiC van der Waals (vdW) heterostructures under an influence of normal strain and an external electric field have been investigated by the first-principles method. Our results reveal that the compressive strain has much influence on the band gap of the vdW heterostructures and the band gap monotonically increases from 0.955 to 1.343 eV. The results also imply that electrons are likely to transfer from MoS2 to SiC monolayer due to the deeper potential of SiC monolayer. Interestingly, by applying a vertical external electric field, the results present a parabola-like relationship between the band gap and the strength. As the E-field changes from -0.55 to +0.18 V/Å, the band gap first increases from zero to a maximum of about 1.76 eV and then decreases to zero. The significant variations of band gap are owing to different states of Mo, S, Si, and C atoms in conduction band and valence band. The predicted electric field tunable band gap of the MoS2/SiC vdW heterostructures is very promising for its potential use in nanodevices.

Electronic Properties of van der Waals Heterostructure of Black Phosphorus and MoS2

“…Since the discovery of graphene (G), two-dimensional (2D) materials have emerged as a kind of most attractive nanomaterials for their high flexibility and fascinating electronic and optical properties. Following the research upsurge on two-dimensional materials, many novel 2D materials, such as hexagonal boron nitride (h-BN), transitional metal dichalcogenides (TMDs), silicone, and phosphorene, have been discovered and investigated. − More recently, researchers have moved their focus on to two-dimensional vertical heterostructures, such as BMLs/MoS 2, G/h-BN, black phosphorus (BP)/BN, BP/TMDs, TMDs/TMDs, , and MoS 2 /SiC, as well as lateral heterostructures, such as TMDs/TMDs , and G/BN, − for the vdW heterojunction formed between participating materials. This strategy could not only overcome the lattice mismatch-induced defects in participating materials synthesized by epitaxial growing (for vertical stacking) but can also induce excellent physical properties, thus leading to some very intriguing phenomena such as Hofstadter’s butterfly spectrum, , strongly bound excitons, , and spin valley polarization. , …”

Electronic and Optical Properties of van der Waals Heterostructures Based on Two-Dimensional Perovskite (PEA)2PbI4 and Black Phosphorus

“…The excellent transport properties of BP, such as a high hole mobility up to 1000 cm 2 V –1 s –1 , make BP have potential applications in low dimensional electronics and optoelectronics . Recently, researchers have turned their attention to 2D heterostructures, which are designed by stacking two or more different 2D materials through vdW interactions, such as, G/h-BN, BP/BN, BP/TMDs, − 2D perovskite/TMDs, − and MoS 2 /SiC . The vdW heterostructures not only break through the application limits of a single material but can also effectively solve the problem of interface disorder in traditional 3D heterojunctions − In addition, 2D heterostructures have exhibited unique physics as compared with 2D homo-bilayers due to vdW interactions. , 2D heterostructures can exhibit the characteristics of insulators, semiconductors, metals, semimetals, topological insulators, and superconductors and have broad applications in field-effect transistor fields, photodetectors, electrocatalysis, and energy storage devices. − For example, Wang et al demonstrated that tunnel field-effect transistors based on the BP/InSe heterojunction exhibit negative differential resistance and a large on/off current ratio of up to 10 8 when applying low voltages .…”

“…27 Recently, researchers have turned their attention to 2D heterostructures, which are designed by stacking two or more different 2D materials through vdW interactions, such as, G/h-BN, 28 BP/ BN, 29 BP/TMDs, 30−32 2D perovskite/TMDs, 33−36 and MoS 2 / SiC. 37 The vdW heterostructures not only break through the application limits of a single material but can also effectively solve the problem of interface disorder in traditional 3D heterojunctions 38−40 In addition, 2D heterostructures have exhibited unique physics as compared with 2D homo-bilayers due to vdW interactions. 36 However, few theoretical and experimental works report the photoelectric properties of the vdW heterostructure based on 2D perovskites and BP.…”