Indirect excitons in van der Waals heterostructures at room temperature

TL;DR

This paper reports the observation of stable, long-lived indirect excitons at room temperature in van der Waals heterostructures of transition-metal dichalcogenides, enabling potential high-temperature excitonic devices.

Contribution

First demonstration of room-temperature indirect excitons in TMD heterostructures with gate-tunable energy and significantly extended lifetimes.

Findings

Room-temperature stability of IXs in TMD heterostructures

Longer lifetimes of IXs compared to direct excitons

Gate control of exciton energy

Abstract

Indirect excitons (IXs) in van der Waals transition-metal dichalcogenide (TMD) heterostructures are characterized by a high binding energy making them stable at room temperature and giving the opportunity for exploring fundamental phenomena in excitonic systems and developing excitonic devices operational at high temperatures. We present the observation of IXs at room temperature in van der Waals TMD heterostructures based on monolayers of MoS$_2$ separated by atomically thin hexagonal boron nitride. The IXs realized in the TMD heterostructure have lifetimes orders of magnitude longer than lifetimes of direct excitons in single-layer TMD, and their energy is gate controlled.