DO:10.1038/NMAT2858 SUPPLEMENTARY INFORMATION '4',all other modes modulate occupation of the nt bands only near the Fermi level.Their electron fluctuations in real space are similar to the one shown in the contour plot.Therefore,only the mode '4'is unique to give enhanced IR absorption. Section 2. Ruling out the other possibilities for a contribution at 800 cm: 1.Issues related to nitridation during wet chemical reduction:Although the mechanism of chemical reduction is not well understood,and some of the IR peaks (1000-1400 cm)cannot be unambiguously assigned (Supplementary Fig.S6c),they are believed to be associated with N- containing species.Indeed,first principle calculations showed that C-N,N-H,N-N,etc.are likely to be formed upon hydrazine reduction [S2].In any case,this uncertainty does not affect the assignment of aggregated cyclic edge ether at 800 cm. [S2]Kim,M.C.,Hwang,G.S.,Ruoff,R.S.Epoxide reduction with hydrazine on graphene:a first principles study.J.Chem.Phys.131,064704-5(2009). 2.Issues related to silicon carbide formation:The unlikely possibility of forming SiC upon thermal annealing is also ruled out based on the work of Blau et al.[S3]who showed that SiC formation could only be achieved on SiO2 substrates in the presence of a metal catalyst such as iron nanoparticles. [S3]Munnoz,E.et al.Synthesis of SiC nanorods from sheets of single-walled carbon nanotubes. Chem.Phys.Lett.359,397-402(2002). NATURE MATERIALS www.nature.com/naturematerials 11nature materials | www.nature.com/naturematerials 11 doi: 10.1038/nmat2858 supplementary information 11 ‘4’, all other modes modulate occupation of the π bands only near the Fermi level. Their electron fluctuations in real space are similar to the one shown in the contour plot. Therefore, only the mode ‘4’ is unique to give enhanced IR absorption. Section 2. Ruling out the other possibilities for a contribution at 800 cm-1: 1. Issues related to nitridation during wet chemical reduction: Although the mechanism of chemical reduction is not well understood, and some of the IR peaks (1000-1400 cm-1) cannot be unambiguously assigned (Supplementary Fig. S6c), they are believed to be associated with N￾containing species. Indeed, first principle calculations showed that C-N, N-H, N-N, etc. are likely to be formed upon hydrazine reduction [S2]. In any case, this uncertainty does not affect the assignment of aggregated cyclic edge ether at 800 cm-1. [S2] Kim, M. C., Hwang, G. S., Ruoff, R. S. Epoxide reduction with hydrazine on graphene: a first principles study. J. Chem. Phys. 131, 064704-5 (2009). 2. Issues related to silicon carbide formation: The unlikely possibility of forming SiC upon thermal annealing is also ruled out based on the work of Blau et al. [S3] who showed that SiC formation could only be achieved on SiO2 substrates in the presence of a metal catalyst such as iron nanoparticles. [S3] Muňnoz, E. et al. Synthesis of SiC nanorods from sheets of single-walled carbon nanotubes. Chem. Phys. Lett. 359, 397–402 (2002)