An Introduction of 2D Materials for Nanophotonic Devices

Light–matter interactions of Two-dimensional (2D) materials can be further modified by directly processing them into specific shapes or by coupling them with artificial nanostructures, and thus nanophotonic devices based on 2D materials can be fabricated. In addition to the aforementioned nanophotonic devices based on 2D materials, researchers have coupled 2D materials with plasmonic, photonic and other on-chip devices to demonstrate other applications, including second harmonic generation enhancement and light-emitting devices. Graphene has been most widely studied in the family of 2D materials because of its high mobility, optical transparency, flexibility, robustness and environmental stability, making it a promising candidate for fundamental research and electrical, optical and optoelectronic applications. The chapter introduces typical 2D semiconductors by summarising their physical and optical properties, including zero-bandgap graphene, mid-bandgap transition metal dichalcogenide (TMD) and phosphorene. It explores the elastic light–matter interactions in 2D TMDs are also extraordinarily strong and can benefit the miniaturisation of future optical devices.