| Autor: |
Wen ECH; Department of Chemistry, University of California, Berkeley, California 94720, United States., Jacobse PH; Department of Physics, University of California, Berkeley, California 94720, United States., Jiang J; Department of Physics, University of California, Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States., Wang Z; Department of Physics, University of California, Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States., Louie SG; Department of Physics, University of California, Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States., Crommie MF; Department of Physics, University of California, Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.; Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States., Fischer FR; Department of Chemistry, University of California, Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.; Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.; Bakar Institute of Digital Materials for the Planet, Division of Computing, Data Science, and Society, University of California, Berkeley, California 94720, United States. |
| Abstrakt: |
Substitutional heteroatom doping of bottom-up engineered 1D graphene nanoribbons (GNRs) is a versatile tool for realizing low-dimensional functional materials for nanoelectronics and sensing. Previous efforts have largely relied on replacing C-H groups lining the edges of GNRs with trigonal planar N atoms. This type of atomically precise doping, however, only results in a modest realignment of the valence band (VB) and conduction band (CB) energies. Here, we report the design, bottom-up synthesis, and spectroscopic characterization of nitrogen core-doped 5-atom-wide armchair GNRs (N 2 -5-AGNRs) that yield much greater energy-level shifting of the GNR electronic structure. Here, the substitution of C atoms with N atoms along the backbone of the GNR introduces a single surplus π-electron per dopant that populates the electronic states associated with previously unoccupied bands. First-principles DFT-LDA calculations confirm that a sizable shift in Fermi energy (∼1.0 eV) is accompanied by a broad reconfiguration of the band structure, including the opening of a new band gap and the transition from a direct to an indirect semiconducting band gap. Scanning tunneling spectroscopy (STS) lift-off charge transport experiments corroborate the theoretical results and reveal the relationship among substitutional heteroatom doping, Fermi-level shifting, electronic band structure, and topological engineering for this new N-doped GNR. |
