Nanoantenna-Enhanced Light–Matter Interaction in Atomically Thin WS2

Atomically thin transition metal dichalcogenides (TMDCs) are an emerging class of two-dimensional semiconductors. Recently, the first optoelectronic devices featuring photodetection as well as electroluminescence have been demonstrated using monolayer TMDCs as active material. However, the light–matter coupling for atomically thin TMDCs is limited by their small absorption length and low photoluminescence quantum yield. Here, we significantly increase the light–matter interaction in monolayer tungsten disulfide (WS2) by coupling the atomically thin semiconductor to a plasmonic nanoantenna. Due to the plasmon resonance of the nanoantenna, strongly enhanced optical near-fields are generated within the WS2 monolayer. We observe an increase in photoluminescence intensity by more than 1 order of magnitude, resulting from a combined absorption and emission enhancement of the exciton in the WS2 monolayer. The polarization characteristics of the coupled system are governed by the nanoantenna. The robust nanoantenna–monolayer hybrid paves the way for efficient photodetectors, solar cells, and light-emitting devices based on two-dimensional materials.