MoS₂ monolayers on nanocavities: Enhancement in light-matter interaction

Two-dimensional (2D) atomic crystals and van der Waals heterostructures constitutean emerging platform for developing new functional ultra-thin electronic and optoelectronic materials for novel energy-efficient devices. However, in most thin-film optical applications, there is a long-existing trade-off between the effectiveness of light-matter interactions and the thickness of semiconductor materials, especially when the materials are scaled downtoatom thick dimensions. Consequently, enhancement strategies can introduce significant advances to these atomically thick materials and devices. Here wedemonstrate enhanced absorption and photoluminescence generation from MoS₂ monolayers coupled with aplanar nanocavity. This nanocavity consistsofan alumina nanolayer spacer sandwiched between monolayer MoS₂ and analuminum reflector, and can strongly enhance the light-matter interaction within the MoS₂, increasing the exclusive absorptionofmonolayer MoS₂ to nearly 70%at awavelengthof450 nm. The nanocavity also modifies the spontaneous emission rate, providing an additional design freedom to control the interaction between light and 2D materials.