Normal Strain-Induced Tunneling Behavior Promotion in van der Waals Heterostructures*

Abstract

Van der Waals heterostructures (vdWHs) realized by vertically stacking of different two-dimensional (2D) materials are a promising candidate for tunneling devices because of their atomically clean and lattice mismatch-free interfaces in which different layers are separated by the vdW gaps. The gaps can provide an ideal electric modulation environment on the vdWH band structures and, on the other hand, can also impede the electron tunneling behavior because of large tunneling widths. Here, through first-principles calculations, we find that the electrically modulated tunneling behavior is immune to the interlayer interaction, keeping a direct band-to-band tunneling manner even the vdWHs have been varied to the indirect semiconductor, which means that the tunneling probability can be promoted through the vdW gap shrinking. Using transition metal dichalcogenide heterostructures as examples and normal strains as the gap reducing strategy, a maximum shrinking of 33% is achieved without changing the direct tunneling manner, resulting in a tunneling probability promotion of more than 45 times. Furthermore, the enhanced interlayer interaction by the strains will boost the stability of the vdWHs at the lateral direction, preventing the interlayer displacement effectively. It is expected that our findings provide perspectives in improving the electric behaviors of the vdWH devices.

A novel two-dimensional SiO sheet with high-stability, strain tunable electronic structure, and excellent mechanical properties*

“…Strain is an effective method to control the electronic properties of 2D materials. [34][35][36][37][38][39] In order to further study the regulation of strain on the 2D P2, we conduct a study on the regulation of strain on electronic properties. Firstly, we conduct a study on the adjustment of the electronic properties of the 2D structure by uniaxial strain along the a direction, as shown in Fig.…”

Harnessing the Defects at Hetero‐Interface of Transition Metal Compounds for Advanced Charge Storage: A Review

“…According to the degree of mismatch between the lattice constants, the interface can be categorized as a coherent interface, semi‐coherent interface, or incoherent interface. [ 119,122–125 ] A coherent interface forms when the lattice constants of the two materials are only slightly different. In this case, the materials can adapt to the epitaxial strain through a local lattice phase change, which avoids altering the structure.…”

Polarized photoluminescence spectroscopy in WS2, WSe2 atomic layers and heterostructures by cylindrical vector beams*

“…The formation of 2D Van der Waals heterostructures [20,21] combines the advantages of individual materials and offers new means to manipulate physical properties. [22][23][24][25] In addition, interlayer excitons in TMDCs heterostructures, which are formed with electrons and holes located in different materials and layers, [21] can be obtained and the energy can be tuned by choosing different 2D martials. [26] Interlayer excitons play a key role in the application of heterojunctions due to the long lifetime, valley related properties, and tunability with an applied electric field.…”