Enabling remote quantum emission in 2D semiconductors via porous metallic networks

TL;DR

This study demonstrates how porous metallic networks on 2D semiconductors enable efficient surface plasmon coupling and non-local single-photon emission, advancing quantum optics applications.

Contribution

It introduces a novel OPEN film geometry that supports plasmonic coupling and quantum light emission in 2D semiconductors, with potential for quantum optics.

Findings

Formation of textured gold films with pore networks after annealing.

Support for surface plasmon-polaritons in OPEN films enabling photon emission.

Observation of non-local single-photon emission at 17 μm distance.

Abstract

The interaction between two-dimensional crystals (2DCs) and metals is ubiquitous in 2D material research. Here we report how 2DC overlayers influence the recrystallization of relatively thick metal films and the subsequent synergetic benefits this provides for coupling surface plasmon-polaritons (SPPs) to photon emission in 2D semiconductors. We show that annealing 2DC/Au films on SiO2 results in a 'reverse epitaxial' process where initially nanocrystalline Au films become highly textured and in close crystallographic registry to the 2D crystal overlayer. With continued annealing, the metal underlayer dewets to form an oriented pore enabled network (OPEN) film in which the 2DC overlayer remains suspended above or coats the inside of the metal pores. This OPEN film geometry supports SPPs launched by either direct laser excitation or by light emitted from the TMD semiconductor itself, where energy in-coupling and out-coupling occurs at the metal pore sites such that dielectric spacers between the metal and 2DC layer are unnecessary. At low temperatures a high density of single-photon emitters (SPEs) is present across an OPEN-WSe2 film, and we demonstrate non-local excitation of SPEs at a distance of 17 {\mu}m with minimal loss of photon purity. Our results suggest the OPEN film geometry is a versatile platform that could facilitate the use of layered materials in quantum optics systems.