Interlayer Exciton in Transition Metal Dichalcogenide Semiconductors for 2D Optoelectronics.

Optoelectronic materials that allow on-chip integrated light signal emitting, routing, modulation, and detection are crucial for the development of high-speed and -throughput optical communication and computing technologies. Interlayer excitons in 2D van der Waals heterostructures, where electrons and holes are bounded by Coulomb interaction but spatially localized in different 2D layers, have recently attracted intense attentions for their enticing properties and huge potentials in device applications. Here, we present a general view of these 2D-confined hydrogen-like bosonic particles and the state-of-the-art developments with respect to the frontier concepts and prototypes. Staggered type-II band alignment enabled us to expand the interlayer direct bandgap from the intrinsic visible in monolayers up to near or even mid-infrared spectrum. Owing to large exciton binding energy together with ultra-long lifetime, room-temperature exciton devices and observation of quantum behaviours have been demonstrated. With the rapid advances, we can anticipate that future studies of interlayer excitons will not only allow us to construct all-exciton information processing circuits but also continue to enrich the panoply of ideas on quantum phenomena. This article is protected by copyright. All rights reserved.