Engineering anisotropy in 2D transition metal dichalcogenides via heterostructures
Biao Wu, Xing Xie, Zheng Haihong, Shaofei Li, Junnan Ding, Jun He, Zongwen Liu, Yanping Liu
Abstract
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 creation of heterostructures (HSs) by stacking highly symmetric MoSe 2 with low-symmetry ReS 2 , introducing artificial anisotropy into monolayer MoSe 2 . Through a meticulous analysis of angle-dependent photoluminescence (PL) spectra, 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 MoSe 2 . This intriguing behavior can be attributed to the in-plane polarization of MoSe 2 , incited by the deliberate disruption of lattice symmetry within the monolayer MoSe 2 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.