| Full text | |
| Author(s): |
Querne, Mateus B. P.
;
Bracht, Jean M.
;
Da Silva, Juarez L. F.
;
Janotti, Anderson
;
Lima, Matheus P.
Total Authors: 5
|
| Document type: | Journal article |
| Source: | PHYSICAL REVIEW B; v. 108, n. 8, p. 11-pg., 2023-08-07. |
| Abstract | |
Two-dimensional (2D) semiconductor materials offer a platform for unconventional applications such as valleytronics, flexible nanoelectronics, and hosts of quantum emitters. Many of these materials and their electronic properties remain to be explored. Using ab initio simulations based on the density functional theory, we investigate group-IV monochalcogenides MQ (M = Si, Ge, Sn and Q = S, Se, Te), an emerging class of 2D materials, with two competing crystal structures: (i) phosphorenelike (Pmn21), which has already been synthesized, and (ii) SiTe-type (P3 over bar m1), which has been much less explored. Except for SnS, we find that the SiTe type is the lowest-energy structure and has higher structural stability, motivating efforts to synthesize this less explored P3 over bar m1 phase. Regarding the optoelectronic properties of these two phases, in the P3 over bar m1 phase, MQ compounds have band gaps around the sunlight spectrum peak and show narrower variations in band gap with the composition and higher absorption coefficients for lighter chalcogens. In contrast, in the Pmn21 phase, MQ compounds have wider band gaps and show a band gap variation of up to 72% with composition, higher absorption coefficients with Te atoms, and potential for valleytronics. In particular, SiS shows interesting high optical anisotropy among all the investigated materials. Furthermore, the optical spectra present peaks that are particular to each phase or composition, making the refractive index a distinguishing parameter for identifying the different MQ compounds. Finally, a phase transition from monolayer to bulk due to an interaction between the layers is observed. Thus, the present results straighten out the role of the crystalline phase in the optoelectronic properties of these monochalcogenides. (AU) | |
| FAPESP's process: | 17/11631-2 - CINE: computational materials design based on atomistic simulations, meso-scale, multi-physics, and artificial intelligence for energy applications |
| Grantee: | Juarez Lopes Ferreira da Silva |
| Support Opportunities: | Research Grants - Research Centers in Engineering Program |
| FAPESP's process: | 18/21401-7 - Multi-User Equipment approved in grant 2017/11631-2: cluster computational de alto desempenho - ENIAC |
| Grantee: | Juarez Lopes Ferreira da Silva |
| Support Opportunities: | Multi-user Equipment Program |