2D materials for Near-infrared Quantum Light Emission

In this presentation, I will discuss the site-controlled generation of near-infrared (NIR) single-photon emitters (SPEs) in various two-dimensional (2D) material systems, including transition metal dichalcogenides, metal monochalcogenides, and heterostructures. Utilizing a scalable technique, we induce the emission of non-classical light through the precise implantation of localized strain and defect centers. The induced excitons, trapped by strain-induced potential wells and recombining at defect energy levels, produce bright, narrow-bandwidth photoluminescence (PL) with emission wavelengths spanning 900 nm to 1.6 μm, encompassing the critical telecom bands. Our Hanbury Brown and Twiss (HBT) experiments exhibit clear photon antibunching, unequivocally confirming the quantum nature of these emitters. Combining density functional theory (DFT) with scanning tunneling microscopy/spectroscopy (STM/STS) studies, we elucidate how the energy band structures are modulated by strain and various defect states, providing insights into the origin of quantum emissions.

I will begin by introducing my pioneering work on creating two-dimensional single-photon emitters (SPEs) in narrow-bandgap 2D materials, specifically focusing on molybdenum telluride (MoTe2), a transition metal dichalcogenide, and indium selenide (InSe), a metal monochalcogenide. Following this, I will delve into the material and layer number engineering of multilayer InSe to illustrate how SPEs can be controllably generated at specific locations and wavelengths. Additionally, I will explore the impact of various defect centers, including selenium vacancies, oxygen substitutions, and helium implantations, on the optical properties of InSe. All findings are substantiated by low-temperature optical spectroscopy, time-tagged time-correlated photon statistics, and DFT calculations. Lastly, I will briefly discuss my efforts to integrate these newly developed 2D NIR SPEs with photonic structures to elevate the operating temperature and enhance brightness.