Engineering of excitonic emission and valley polarization enhancement in two-dimensional semiconductors

Atomically thin two-dimensional transition metal dichalcogenides have garnered tremendous attention from researchers owing to their distinct electrical and optical properties. Improving the photoluminescence of these two-dimensional atomic semiconductors is imperative for their seamless integration into photonic and optoelectronic devices. Concurrently, the advent of two-dimensional materials such as graphene and transition metal dichalcogenides has ushered in opportunities within the realm of valleytronics. Valleytronics endeavors to exploit valley degrees of freedom for information processing, mirroring the principles of spin-based spintronics and charge-based electronics. Notably, these materials demonstrate a unique spin-valley locking mechanism, thereby enabling modulation of the electronic valley degree of freedom through light. In the present study, we fabricated cost-effective nanocone structures via colloidal lithography and subsequently integrated them with a monolayer of WSe₂. Through this methodology, we amplified both the photoluminescence and valley polarization enhancement of the WSe₂ monolayer by harnessing plasmonic hotspots.