PT - JOURNAL ARTICLE AU - Kawai, Shigeki AU - Nakatsuka, Soichiro AU - Hatakeyama, Takuji AU - Pawlak, Rémy AU - Meier, Tobias AU - Tracey, John AU - Meyer, Ernst AU - Foster, Adam S. TI - Multiple heteroatom substitution to graphene nanoribbon AID - 10.1126/sciadv.aar7181 DP - 2018 Apr 01 TA - Science Advances PG - eaar7181 VI - 4 IP - 4 4099 - http://advances.sciencemag.org/content/4/4/eaar7181.short 4100 - http://advances.sciencemag.org/content/4/4/eaar7181.full SO - Sci Adv2018 Apr 01; 4 AB - Substituting heteroatoms into nanostructured graphene elements, such as graphene nanoribbons, offers the possibility for atomic engineering of electronic properties. To characterize these substitutions, functionalized atomic force microscopy (AFM)—a tool to directly resolve chemical structures—is one of the most promising tools, yet the chemical analysis of heteroatoms has been rarely performed. We synthesized multiple heteroatom-substituted graphene nanoribbons and showed that AFM can directly resolve elemental differences and can be correlated to the van der Waals radii, as well as the modulated local electron density caused by the substitution. This elemental-sensitive measurement takes an important step in the analysis of functionalized two-dimensional carbon materials.