Anisotropic optical characteristics of WS2/ReS2 heterostructures with broken rotational symmetry

High-symmetry transition-metal dichalcogenides (TMDs) have garnered substantial attention in the fields of sensors, optoelectronics, and valleytronics. However, the inherent C3 rotational symmetry of TMDs engenders highly isotropic properties, impeding their further technological progress. To overcome this limitation, we embarked on a study to investigate the effects of isotropic/anisotropic heterostructures engineering on WS2, aiming to break its C3 rotational symmetry. In this work, we designed and fabricated heterostructures composed of WS2 and ReS2 layers. Our comprehensive investigations revealed a remarkable emergence of anisotropic characteristics in excitons originating from the WS2 layers within the engineered WS2/ReS2 heterostructures. Moreover, we observed an enhancement in the valley polarizations of WS2 layers within the heterostructures, which is attributed to the reduced intervalley scattering facilitated by the WS2/ReS2 heterostructure configuration. This observation indicates the potential for leveraging heterostructure engineering to tailor and optimize anisotropic devices, thereby opening promising avenues for future applications in various technological domains.