Emission engineering in van der Waals materials

Abstract

In this talk I will discuss about the integration of two-dimensional materials, specifically hexagonal boron nitride (hBN) and transition metal dichalcogenide (WSe2), with our recently developed plasmonic nanocone platform, unlocking new possibilities in classical and quantum optical emission engineering. The fabrication of the nanocones was carried out using both low-cost colloidal lithography and conventional lithographic techniques, depending on the application. On the quantum side, we focused on hBN, investigating its single-photon emission coupled with gold nanocones. While revealing a dual functionality of emission activation due to induced strain and enhancement via plasmonic effect, discerning the exact emission origin proves intricate due to the intrinsic fluorescence of gold. On the classical side, we address integration challenges with WSe2, presenting a plasmon-enhanced nanocone platform, surpassing conventional fabrication methods and enhancing the photoluminescence in WSe2 monolayers. This enhancement allows precise engineering of exciton and trion contributions to emission. Moreover, our investigation highlights the critical role of plasmonic enhancement in valleytronics in TMDCs, particularly WSe2. The integration of cost-effective nanocone structures enhances the photoluminescence as well as valley polarization synergistically through plasmonic hotspots. The presented integrated platforms are expected to advance both the fundamental understanding of material systems as well as open avenues for next-generation photonic, optoelectronic, and quantum technologies.