Two-dimensional (2D) material–organic interfaces offer a platform to realize hybrid materials with tunable optical properties that are determined by the interactions between the disparate materials. This is particularly attractive for tailoring the optoelectronic properties of semiconducting monolayer transition metal dichalcogenides (TMDs). Here, we demonstrate evidence of coupled 2D semiconductor–molecular excitons with enhanced optical properties, which results from the atomically thin heterojunction. Specifically, we investigate the hybridization of the 2.16 eV WSe2 B exciton with the 2.20 eV transition of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), observed by enhanced resonant Raman scattering by the PTCDA vibrational modes, with enhancements by a factor of nearly 20. The effect can be understood from a coupled oscillator model in which the strong absorption resonance of the WSe2 monolayer increases the Raman scattering efficiency of the PTCDA. The Raman enhancement diminishes with increasing WSe2 thickness, which is attributed to a reflectivity effect that reduces the intensity at the surface. The proposed hybridization effect may lead to new investigations into the nature of coupled excitons in atomically thin junctions.
Electronic interactions associated with atomic adsorbates on van der Waals layered transition-metal dichalcogenides such as MoS2 can induce massive electronic reconstruction that results in the formation of a metallic phase that exhibits characteristics of a two-dimensional electron gas. The impact and mechanism of quantum confinement and reduced dimensionality on the carrier dynamics in such two-dimensional systems is at present not known, but it is of paramount importance, if they are to find application in optoelectronic devices. Here, we show by a combination of angle-resolved photoemission and advanced X-ray spectroscopies that many-body interactions in reduced dimension drastically shorten carrier lifetimes and reveal how potassium intercalation in MoS2 forces orbital rehybridization to create a two-dimensional electron gas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.