Bright visible light emission from graphene

Graphene and related two-dimensional materials are promising candidates for atomically thin, flexible and transparent opto-electronics(1,2). In particular, the strong light-matter interaction in graphene(3) has allowed for the development of state-of-the-art photodetectors(4,5), optical modulators(6) and plasmonic devices(7). In addition, electrically biased graphene on SiO2 substrates can be used as a low-efficiency emitter in the mid-infrared range(8,9). However, emission in the visible range has remained elusive. Here, we report the observation of bright visible light emission from electrically biased suspended graphene devices. In these devices, heat transport is greatly reduced(10). Hot electrons (similar to 2,800 K) therefore become spatially localized at the centre of the graphene layer, resulting in a 1,000-fold enhancement in thermal radiation efficiency(8,9). Moreover, strong optical interference between the suspended graphene and substrate can be used to tune the emission spectrum. We also demonstrate the scalability of this technique by realizing arrays of chemical-vapour-deposited graphene light emitters. These results pave the way towards the realization of commercially viable large-scale, atomically thin, flexible and transparent light emitters and displays with low operation voltage and graphene-based on-chip ultrafast optical communications.