Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures

TL;DR

This paper reports the observation of bright, room-temperature interface excitons in mixed-dimensional heterostructures of tungsten diselenide and carbon nanotubes, with potential applications in quantum photonics.

Contribution

It demonstrates the first room-temperature detection of interface excitons in mixed-dimensional heterostructures and explores their optical properties and potential for quantum photonics.

Findings

Interface excitons are observed at room temperature.

The excitons exhibit single-photon emission characteristics.

Band alignment influences the excitonic properties.

Abstract

The development of van der Waals heterostructures has introduced unconventional phenomena that emerge at atomically precise interfaces. For example, interlayer excitons in two-dimensional transition metal dichalcogenides show intriguing optical properties at low temperatures. Here we report on room-temperature observation of interface excitons in mixed-dimensional heterostructures consisting of two-dimensional tungsten diselenide and one-dimensional carbon nanotubes. Bright emission peaks originating from the interface are identified, spanning a broad energy range within the telecommunication wavelengths. The effect of band alignment is investigated by systematically varying the nanotube bandgap, and we assign the new peaks to interface excitons as they only appear in type-II heterostructures. Room-temperature localization of low-energy interface excitons is indicated by extended lifetimes as well as small excitation saturation powers, and photon correlation measurements confirm single-photon emission. With mixed-dimensional van der Waals heterostructures where band alignment can be engineered, new opportunities for quantum photonics are envisioned.