Strain Engineering on the Electronic and Optical Properties of WSSe Bilayer

Abstract

Controllable optical properties are important for optoelectronic applications. Based on the unique properties and potential applications of two-dimensional Janus WSSe, we systematically investigate the strain-modulated electronic and optical properties of WSSe bilayer through the first-principle calculations. The preferred stacking configurations and chalcogen orders are determined by the binding energies. The bandgap of all the stable structures are found sensitive to the external stress and could be tailored from semiconductor to metallicity under appropriate compressive strains. Atomic orbital projected energy bands reveal a positive correlation between the degeneracy and the structural symmetry, which explains the bandgap evolutions. Dipole transition preference is tuned by the biaxial strain. A controllable transformation between anisotropic and isotropic optical properties is achieved under an around − 6%~− 4% critical strain. The strain controllable electronic and optical properties of the WSSe bilayer may open up an important path for exploring next-generation optoelectronic applications.

Tuning the physical properties of ultrathin transition-metal dichalcogenides via strain engineering

“…Different from the almost unaffected electronic properties of graphene under strain, the electronic properties of ultrathin TMDs are signicantly sensitive to almost all types of mechanical strain, namely shear strain, tensile strain and compressive strain, the strain-induced electronic structural evolution will undoubtedly result in the modication of optical and electrical transport properties. [63][64][65][66] For instance, the existence of continuously varying local strain on few-layer MoS 2 bubbles can lead to an increasing PL intensity from the center of the bubble to the edge due to the strain-induced indirect to direct bandgap transition, which greatly extends the application of these materials in optoelectronic devices 67 (Fig. 3a-d).…”

“…86 In addition, dipole transition preference of ultrathin TMDs can be investigated from their dielectric properties, thus, the studies on the strain-induced dielectric properties of ultrathin TMDs are of great signicant in fabricating nanoelectromechanical devices. 66,87 According to the previous density functional theory (DFT) calculations, the dielectric properties of ultrathin TMDs are strongly dependent on the type of strain. For monolayer MoX 2 (X ¼ S, Se, Te), tensile strain showed a stronger displacement towards lower energy in the imaginary part of dielectric function when compared to compression strain, and the application of tensile strain and asymmetric biaxial strain lead to the increase of static dielectric constant, while the application of compression strains result in the rst decrease and then increase of static dielectric constant.…”

Electronic structure of strain-tunable Janus WSSe–ZnO heterostructures from first-principles

“…Our calculated a -lattice parameter for ZnO is in agreement with prior work, 40 as is that of WSSe. 41 A vacuum layer of ∼25 Å is included in our supercells, as are dipole corrections along the c -axis to account for the finite out-of-plane dipole moments of these heterostructures. Binding energies of different stacking orientations are calculated using E B = E WSSe–ZnO − E WSSe − E ZnO , comparing the total energy of the heterostructures to the energies of the isolated monolayers.…”

Enhanced Opto‐Electrical Properties of Chalcogenide‐Rich Tin Selenide Thin Film after Incorporating Sulfur Yielding Tin Sulfoselenide

“…Thermal Evaporation [44] 2.27×10 À 2 6.1 4.53×10 19 p Co-evaporation [45] 1.96×10 À 2 24.8 1.08×10 19 p…”

“…For optoelectronic devices and applications, different ternary sulfo-selenides, including CdSSe, SnSSe, ZnSSe, WSSe, Sb 2 SSe, and MoSSe, have been demonstrated in numerous investigations. [15][16][17][18][19][20][21][22][23] Tin (II) sulfoselenide (SnSSe), one of the sulfosalt materials on which we focus, has demonstrated promising performance for a wide range of applications in optoelectronic devices owing to its advantageous electrical and optical properties, which fall in between those of SnS and SnSe. [22,23] Numerous researchers have noted that SnSe exhibits a single phase when Se/Sn > 1.…”