A first-principles study of electronic and optical properties of the tetragonal phase of monolayer ZnS modulated by biaxial strain

Abstract

The evolution of electronic property for monolayer tetragonal ZnS under biaxial strain.

Influence of Group-IVA Doping on Electronic and Optical Properties of ZnS Monolayer: A First-Principles Study

“…To explore the influence of element doping on the electronic structure of the ZnS monolayer, the band structures of the ZnS monolayer, C−ZnS, Si−ZnS, Ge−ZnS, Sn−ZnS, and Pb−ZnS are calculated, as displayed in Figure 4 . In line with the previous studies [ 29 , 30 ], the ZnS monolayer has a direct band gap of 2.91 eV, in which both the valence band maximum (VBM) and conduction band minimum (CBM) are located at the Γ point. When one Zn atom is replaced by C, Si, Ge, Sn, and Pb atoms, respectively, both the VBM and CBM of these doped models are still located at the Γ point, demonstrating that the doped models retain the direct band gaps.…”

“…The kinetic energy cutoff was set to 500 eV, and k-point meshes of 10 × 10 × 1 were chosen from the Brillouin zone with the Monkhorst–Pack method [ 35 ]. Based on the primitive cell of the ZnS monolayer with the tetragonal phase in our previous study [ 29 ], a 3 × 3 supercell was built, composed of 18 Zn and 18 S atoms, with a vacuum thickness of 20 Å. By replacing one Zn atom in the supercell with the group-ⅣA element (C, Si, Ge, Sn, and Pb), the doped ZnS models were obtained with a doping fraction of 2.8% (i.e., C−ZnS, Si−ZnS, Ge−ZnS, Sn−ZnS, and Pb−ZnS).…”

“…Similar to many 2D materials with more than one allotrope [ 4 , 23 , 24 ], the graphene-like ZnS monolayer also has an allotrope [ 25 ], which exhibits a tetragonal phase just like monolayer CdTe [ 26 ], CdSe [ 27 ], CdS [ 27 ], and ZnSe [ 28 ]. In our previous study, we have explored the influence of strain on the electronic and optical properties of the tetragonal ZnS [ 29 ], but a more complete understanding of monolayer tetragonal ZnS is still insufficient [ 30 ].…”

Janus Zn‐IV‐VI: Robust Photocatalysts with Enhanced Built‐In Electric Fields and Strain‐Regulation Capability for Water Splitting

“…[56] In addition, the ZnSnTe 2 monolayer has high absorption coefficients of (0.3−8) × 10 4 cm −1 in the visible light range (1.6−3.2 eV), which surpass various 2D materials such as monolayer ZnS, In 2 Se 3 , and conventional Ga 2 XY/In 2 XY (X/Y = S/Se/Te, X ≠ Y) of the coefficients up to ≈(0.3−4) × 10 4 cm −1 . [6c, 28,44] The width of the bandgap calculated by the GW 0 method (E GW ) includes barriers of the electron transition energy (optical bandgap) and the quasiparticle binding energy. Hence, to determine the binding energy of the excitons, the difference between E GW and the corresponding energy of the initial GW 0 + BSE absorption peak is computed.…”

“…Furthermore, tetragonal ZnS shows high potential in terms of photon utilization and strain sensitivity on electronic structures and optical absorption. [ 28 ] Hence, the mechanically enhanced photocatalysis of Janus ZnXY 2 holds significant potential due to the induced piezoelectric polarization charges, which effectively suppress the recombination of photogenerated carriers. [ 29 ] Consequently, the doping‐free Janus ZnXY 2 membranes should exhibit promising capabilities in photon absorption and the directional modification of dipole moments, thereby fulfilling the aforementioned three pivotal conditions.…”