Vertical van der Waals Heterostructure of Single Layer InSe and SiGe

Abstract

We present a first-principles investigation on the stability, electronic structure and mechanical response of ultra-thin heterostructure composed of single layers of InSe and SiGe. First, by performing total energy optimization and phonon calculations, we show that single layers of InSe and SiGe can form dynamically stable heterostructures in 12 different stacking types. Valence and conduction band edges of the heterobilayers form a type-I heterojunction having a tiny bandgap ranging between 0.09-0.48 eV. Calculations on elastic-stiffness tensor reveal that two mechanically soft single layers form a heterostructure which is stiffer than constituent layers due to relatively strong interlayer interaction. Moreover, phonon analysis show that the bilayer heterostructure has highly Raman active modes at 205.3 and 43.7 cm −1 , stemming from out-of-plane interlayer mode and layer breathing mode, respectively. Our results show that, as a stable type-I heterojunction, ultra-thin heterobilayer of InSe/SiGe holds promise for nanoscale device applications.

Direct band gap and strong Rashba effect in van der Waals heterostructures of InSe and Sb single layers

“…We first investigate the properties of the separate InSe and Sb single layers. The optimized lattice parameters of InSe and Sb single layers are 4.026 Å and 4.064 Å, respectively, which are in good agreement with previous calculations [46,47]. Their band structures and band gaps calculated without and with SOC are presented in Fig.…”

Rotation Tunable Type‐I/Type‐II Band Alignment and Photocatalytic Performance of g‐C3N4/InSe van der Waals Heterostructure

“…The calculated lattice constants for g-C 3 N 4 and InSe MLs are a 1 ¼ b 1 ¼ 7.142 Å and a 2 ¼ b 2 ¼ 4.084 Å, respectively, which are in good consistence with the previous reports. [19,[29][30][31] Note that the lattice constants are, herein, in the level of GGA-PBE. We load a fixed 1  1 g-C 3 N 4 on the rotated ffiffi ffi 3 p  ffiffi ffi 3 p InSe supercell with the angles of 0 , 60 , and 120 to construct three different stacking configurations of CNIS HSs (see Figure 1), which are also called CNIS (i), (ii), and (iii).…”

InSe/Te van der Waals Heterostructure as a High-Efficiency Solar Cell from Computational Screening

“…Van der Waals (vdW) heterostructures are stacked by two or more two-dimensional (2D) materials with only vdW interaction in their interlayers but no surface dangling bonds [ 1 ], which were widely used in vertical field-effect transistors [ 2 ], wearable and biocompatible electronics [ 3 ], photodetectors [ 4 ], photovoltaics [ 5 , 6 , 7 ], light-emitting devices (LEDs) [ 8 ], and so on. Because vdW force in the interlayer is a long-range weak interaction, the heterostructures can be formed under the existence of large lattice mismatch among the monolayers [ 9 ].…”

“…Furthermore, vdW heterostructures can combine the excellent properties of the monolayers [ 10 ]. Under the interlayer coupling in vdW heterostructures, they can also exhibit novel characteristics that their components do not possess [ 7 , 11 , 12 , 13 ]. Designing type-II vdW heterostructures for solar cells through band-structure engineering by using calculations is an efficient way, such as graphene/GaAs [ 5 ], Ti 2 CO 2 /Zr 2 CO 2 [ 14 ] and GaSe/GaTe heterostructures [ 15 ].…”

“…Excitingly, 2D InSe was successfully prepared experimentally, which exhibits high electron mobility, quantum Hall effect, and anomalous optical response [ 23 ]. Moreover, the 2D InSe related vdW heterostructures combined with another layers such as graphene [ 24 ], black phosphorus [ 25 ], C 3 N 4 [ 26 ], SiGe [ 7 ], or III–VI monolayers [ 15 , 27 ] attracted remarkable attention for high-performance electronic and optoelectronic devices. Recently, the 1T-MoS 2 -like phase T -Se and α -Te were successfully obtained in the laboratory [ 28 , 29 ].…”