title: Scanning gate spectroscopy and its application to carbon nanotube defects.
abstract: A variation of scanning gate microscopy (SGM) is demonstrated in which this imaging mode is extended into an electrostatic spectroscopy. Continuous variation of the SGM probe's electrostatic potential is used to directly resolve the energy spectrum of localized electronic scattering in functioning, molecular scale devices. The technique is applied to the energy-dependent carrier scattering that occurs at defect sites in carbon nanotube transistors, and fitting energy-resolved experimental data to a simple transmission model determines the electronic character of each defect site. For example, a phenolic type of covalent defect is revealed to produce a tunnel barrier 0.1 eV high and 0.5 nm wide.
authors.affiliation: Department of Physics and Astronomy, University of California at Irvine, Irvine, California 92697, United States.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Hunt
authors.forename: Danny
authors.initials: D
authors.lastname: Wan
authors.forename: Vaikunth R
authors.initials: VR
authors.lastname: Khalap
authors.forename: Brad L
authors.initials: BL
authors.lastname: Corso
authors.forename: Philip G
authors.initials: PG
authors.lastname: Collins
mesh_terms: D008853:Microscopy / Q000379:methods*; D037742:Nanotubes, Carbon; D013057:Spectrum Analysis / Q000379:methods*; D055672:Static Electricity
chemical_list: D037742:Nanotubes, Carbon