Nanoscale trapping of interlayer excitons in a 2D semiconductor heterostructure

TL;DR

This paper demonstrates a novel method to trap interlayer excitons in a 2D heterostructure using nanopatterned graphene gates, advancing quantum technology applications by enabling deterministic exciton placement.

Contribution

It introduces a nanopatterned graphene gate technique for deterministic trapping of interlayer excitons in 2D heterostructures, surpassing previous methods in energy tunability and control.

Findings

Trapped excitons show electric field-dependent energy shifts.

Trapped excitons exhibit increased lifetime and saturation at low power.

The method achieves ~20 nm spatial confinement of excitons.

Abstract

For quantum technologies based on single excitons and spins, the deterministic placement and control of a single exciton is a long-standing goal. MoSe2-WSe2 heterostructures host spatially indirect interlayer excitons (IXs) which exhibit highly tunable energies and unique spin-valley physics, making them promising candidates for quantum information processing. Previous IX trapping approaches involving moir\'e superlattices and nanopillars do not meet the quantum technology requirements of deterministic placement and energy tunability. Here, we use a nanopatterned graphene gate to create a sharply varying electric field in close proximity to a MoSe2-WSe2 heterostructure. The dipole interaction between the IX and the electric field creates an ~20 nm trap. The trapped IXs show the predicted electric field dependent energy, saturation at low excitation power, and increased lifetime, all signatures of strong spatial confinement. The demonstrated architecture is a crucial step towards deterministic trapping of single IXs, which has broad applications to scalable quantum technologies.