ABSTRACT
Graphene is a one-atom-thick sheet of sp2-hybridized carbon atoms arranged in a honeycomb lattice, and thereby the thinnest possible material in nature. A wide range of two-dimensional (2D) materials makes it possible to construct various nanophotonic devices by combining them with different number of layers and compositions. Many 2D materials strongly interact with light and cover a very wide electromagnetic spectrum from microwave to ultraviolet due to their diverse electronic properties. A 2D graphene sheet can be physically regarded as one layer of 3D bulk graphite, but it possesses distinct properties for photonic applications compared to traditional semiconductors. The zero bandgap and linear dispersion of graphene result in very broadband strong absorptance. Graphene is expected to substitute indium tin oxide (ITO) in transparent conductive films used in devices such as light-emitting diodes (LEDs) and organic LEDs (OLEDs), solar cells, touchscreens, smart windows, and liquid crystal display (LCD) films.
