First‐Principles Study of the Electronic and Optical Properties of Bi₂Se₃/MoSe₂ Heterojunction

Abstract

MoSe2 and Bi2Se3 are two kinds of 2D materials that are gradually receiving more attention because of their unique electronic and optical properties. Herein, a Bi2Se3/MoSe2 van der Waals heterojunction (vdWH) is constructed and the electronic and optical properties of the heterojunction are calculated using first‐principles calculations. The effects of the external electric field and the interlayer distance on the electronic properties of the heterojunction are also studied. The calculated results show that the inherent Bi2Se3/MoSe2 vdWH has a type‐2 band alignment with a very small indirect bandgap (28 meV). It also has strong spin–orbit coupling effects, and the characteristics of Zeeman splitting and Rashba splitting are observed at the same time. Both applying an external electric field and changing the interlayer distance can effectively modulate the band structure of the heterojunction; these modulation methods can change the band alignment of the vdWH from type‐2 to type‐3 or even type‐1, and the bandgap type can be changed from indirect to direct. The infrared absorption of the heterojunction is much higher than that of Bi2Se3 and MoSe2. All the calculation results show that the Bi2Se3/MoSe2 vdWH has good application prospects in optoelectronic and spintronic devices.

Tunable band-structures of MSe2/C3N (M = Mo and W) van der Waals Heterojunctions

“…Herein, according to the symmetry of MoSe 2 and C 3 N monolayers, ten different positions of 1 l MoSe 2 on top of C 3 N were considered (such as one of the Mo atoms directly above one of the C or N atoms in figures 2(a) and (b) [41]. The interlayer distance (d) between MoSe 2 and C 3 N monolayer in the heterojunctions is in the range from 3.34 to 3.37Å, which agrees well with other heterojunctions [42][43][44]. Each heterojunction with the different configurations shown in figure 2 has an indirect band gap with the conduction band minimum (CBM) at the M point and corresponding binding energies are listed in table 1.…”

Density Functional Theory Study on the Enhancement Mechanism of the Photocatalytic Properties of the g-C3N4/BiOBr(001) Heterostructure

“…The Fermi level change significantly implies charge redistribution after g-C 3 N 4 coupling to the BiOBr(001) surface. To further confirm this result, the planar average differential charge density of g-C 3 N 4 /BiOBr(001) is calculated according to the following formula 48 where ρ T ( x , y , z ), ρ BiOBr ( x , y , z ), and ρ g-C 3 N 4 ( x , y , z ) represent the charge densities of the g-C 3 N 4 /BiOBr(001) heterojunction, BiOBr(001) surface, and g-C 3 N 4 monolayer, respectively. According to this definition, the positive/negative values of Δρ represent charge accumulation/depletion, respectively.…”