Excitonic Effects in the Linear and Nonlinear Optical Response of Rhenium Disulfide Regulated by Re Vacancy

Abstract

In recent years, the n-type semiconductor ReS 2 , a new member of the TMDs family, exhibits anisotropic physical properties due to its twisted triclinic crystal (1T′) structure and the formation of an extra valence electron in the d orbital to form a Re chain parallel to the b axis (every four Re atoms is a group, referred to as Re 4 ). [12] The conventional 2H-phase TMDs materials when the number of layers changes from single layer to multiple layers, the band gap also changes from direct band gap to indirect band gap. [13][14][15] Figure 1a provides a detailed overview of the structures, morphology and application properties of ReS 2 . For the familiar 2H structure and 1T′ structure, ReS 2 also has a DT-1 and DT-2 structure, as shown in Figure 1a i . K. Dileep et al. [16] used dense functional theory (DFT) to calculate that ReS 2 is a direct bandgap semiconductor regardless of monolayer or block. M. Gehlmann et al. [17] explored the influence of different structures on the band structure of ReS 2 .

Defect and interface/surface engineering synergistically modulated electron transfer and nonlinear absorption properties in MoX2 (X = Se, S, Te)@ZnO heterojunction

“…The luminescence of the A′ peak was obviously enhanced, which is because the defect density is negatively correlated with the photoluminescence intensity. 54 Therefore, the electrons at the DL of MoS 2 are transferred to the CB of ZnO, thereby reducing the defect density of MoS 2 ( process III in Fig. 4(h I )) and enhancing the defect luminescence.…”

Study on interface engineering and chemical bonding of the ReS2@ZnO heterointerface for efficient charge transfer and nonlinear optical conversion efficiency

“…For V Re -ReS 2 , the defect luminescence peak is located near 550 nm, which is about twice the intrinsic luminescence peak, which is consistent with our previous research results. 10 Fig. 4(b ii ) shows PL spectra of the ZnO and V Re -ReS 2 @ZnO heterostructure.…”

“…1(b i -b iii ), V Re -ReS 2 is formed by the self-assembly of nanosheets, and its specific formation process has been reported in detail in the previous research work of this group. 10 According to EDS analysis, the S/Re in ReS 2 samples were 2.48, 2.92, and 2.5, respectively, as shown in Fig. S2(a i -a iii ) (ESI †).…”

“…[1][2][3][4][5][6] There are many methods for the preparation of TMD materials, such as chemical vapor deposition (CVD), mechanical peeling, liquid-phase exfoliation, and hydrothermal methods. [7][8][9][10] Therefore, some vacancies will inevitably appear in the preparation process. 11 The vacancies will affect the physical and chemical properties of TMD materials.…”

“…However the NLA response of ReS 2 is poor, and the saturation absorption (SA) coefficient is low, 26 which seriously hinders its application in ultrafast lasers. Recently, the photoelectric properties of ReS 2 have been modulated by citing V Re 10 and constructing van der Waals heterostructures such as ReS 2 /TiO 2 , 27 ReS 2 /ReSe 2 , 28,29 ReS 2 /WS 2 , 30 and ReS 2 /MoTe 2 31 heterostructures shown in Fig. 1 (b i -ReS 2 heterostructures).…”