Enhancement of Interlayer Exciton Emission in a TMDC Heterostructure via a Multi‐Resonant Chirped Microresonator Upto Room Temperature

• Published in: Advanced materials (Weinheim) 2024-08, Vol.36 (35), p.e2402624-n/a
• Main Authors: Palekar, Chirag C., Rosa, Barbara, Heermeier, Niels, Shih, Ching‐Wen, Limame, Imad, Koulas‐Simos, Aris, Rahimi‐Iman, Arash, Reitzenstein, Stephan
• Format: Article
• Language: English
• Subjects: Bilayers; Bragg reflectors; Broadband DBR; Chirped DBR; Emission analysis; Excitons; Heterostructures; Interlayer exciton enhancement; Interlayers; Microcavities; Microlasers; Multimode coupling; Purcell enhancement; Resonance; Room temperature; Room temperature interlayer exciton; Silicon dioxide; Temperature dependence; Thickness; Transition metal compounds
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202402624

We report on multi‐resonance chirped distributed Bragg reflector (DBR) microcavities. These systems are employed to investigate the light‐mater interaction with both intra‐ and inter‐layer excitons of transition metal dichalcogenide (TMDC) bilayer heterostructures. The chirped DBRs consisting of SiO2 and Si3N4 layers of gradually varying thickness exhibit a broad stopband with a width exceeding 600 nm. Importantly, the structures provide multiple resonances across a broad spectral range, which can be matched to resonances of the embedded TMDC heterostructures. Studying cavity‐coupled emission of both intra‐ and inter‐layer excitons from an integrated WSe2/MoSe2 heterostructure in a chirped microcavity system, an enhanced interlayer exciton emission with a Purcell factor of 6.67 ± 1.02 at 4 K is observed. The cavity‐enhanced emission of the interlayer exciton is used to investigate its temperature‐dependent luminescence lifetime of 60 ps at room temperature. The cavity system modestly suppresses intralayer exciton emission by intentional detuning, thereby promoting a higher IX population and enhancing cavity‐coupled interlayer exciton emission. This approach provides an intriguing platform for future studies of energetically distant and confined excitons in different semiconducting materials, which paves the way for various applications such as microlasers and single‐photon sources by enabling precise emission control and utilizing multimode resonance light‐matter interaction. This study utilizes the multi‐resonant microcavity approach based on chirped distributed Bragg reflectors for enhancement of interlayer exciton from WSe2/MoSe2 heterostructure. A demonstration of effective emitter‐field coupling for the multi‐resonant system has been achieved, with probing of spectrally separated exciton species from the heterostructure. The cavity coupled interlayer excitons exhibits a Purcell factor of 6.67 ± 1.02 at low temperature.