Bright electroluminescence from graphene in the visible range

S1. Fabrication process and characterization of suspended graphene devices S2. Current-induced annealing for high quality contact S3. Stable visible-light emission from suspended graphene S4. Optical measurements and spectrum analysis S5. Beyond black-body radiation formula for visible light emission from suspended graphene: Dependence on the number of graphene layers S6. Effects of absorption and reflection by graphene layers on the emission spectra S7. Negative differential conductance (NDC) and hysteresis behavior in electrically biased suspended mechanically exfoliated (ME) graphene S8. Intrinsic electro-thermal transport model in suspended graphene S9. Thermal radiation power of electrically biased suspended ME graphene S10. SEM image of mechanical failure of suspended graphene after remarkably bright visible light emission under a high electric field Bright visible light e ission from graphene SUPPLEMENTARY INFORMATION DOI: 10.1038/NNANO.2015.118