Engineering anisotropy in 2D transition metal dichalcogenides via heterostructures

Two-dimensional (2D) semiconductors featuring low -symmetry crystal structures hold an immense potential for the design of advanced optoelectronic devices, leveraging their inherent anisotropic attributes. While the synthesis techniques for transition metal dichalcogenides (TMDs) have matured, a promising avenue emerges: the induction of anisotropy within symmetric TMDs through interlayer van der Waals coupling engineering. Here, we unveil the cre-ation of heterostructures (HSs) by stacking highly symmet-ric MoSe2 with low-symmetry ReS2, introducing artificial anisotropy into monolayer MoSe2. Through a meticulous analysis of angle-dependent photoluminescence (PL) spec-tra, we discern a remarkable anisotropic intensity ratio of approximately 1.34. Bolstering this observation, the angle -resolved Raman spectra provide unequivocal validation of the anisotropic optical properties inherent to MoSe2. This intriguing behavior can be attributed to the in-plane polar-ization of MoSe2, incited by the deliberate disruption of lattice symmetry within the monolayer MoSe2 structure. Collectively, our findings furnish a conceptual blueprint for engineering both isotropic and anisotropic HSs, thereby unlocking an expansive spectrum of applications in the realm of high-performance optoelectronic devices. (c) 2023 Optica Publishing Group

Automated summary

This study reveals the possibility of introducing artificial anisotropy in symmetric 2D semiconductors through interlayer van der Waals coupling engineering. By analyzing the photoluminescence spectra and Raman spectra, we discovered the anisotropic optical properties of monolayer MoSe2 and provided a conceptual blueprint for designing isotropic and anisotropic heterostructures.