Scanning probe microwave reflectivity of aligned single-walled carbon nanotubes: Imaging of electronic structure and quantum behavior at the nanoscale

Eric Seabron, Scott MacLaren, Xu Xie, Slava V. Rotkin, John A. Rogers, William L. Wilson

Research output: Contribution to journalArticle


Single-walled carbon nanotubes (SWNTs) are 1-dimensional nanomaterials with unique electronic properties that make them excellent candidates for nextgeneration device technologies. While nanotube growth and processing methods have progressed steadily, significant opportunities remain in advanced methods for their characterization, inspection, and metrology. Microwave near-field imaging offers an extremely versatile "nondestructive" tool for nanomaterials characterization. Herein, we report the application of nanoscale microwave reflectivity to study SWNT electronic properties. Using microwave impedance microscopy (MIM) combined with microwave impedance modulation microscopy (MIM2), we imaged horizontal SWNT arrays, showing the microwave reflectivity from individual nanotubes is extremely sensitive to their electronic properties and dependent on the nanotube quantum capacitance under proper experimental conditions. It is shown experimentally that MIM can be a direct probe of the nanotube-free carrier density and the details of their electronic band structure. We demonstrate spatial mapping of local SWNT impedance (MIM), the density of states (MIM2), and the nanotube structural morphology (AFM) simultaneously and with lateral resolution down to <50 nm. Nanoscale microwave reflectivity could have tremendous impact, enabling optimization of enriched growth processes and postgrowth purification of SWNT arrays while aiding in the analysis of the quantum physics of these important 1D materials.

Original languageEnglish (US)
Pages (from-to)360-368
Number of pages9
JournalACS Nano
Issue number1
StatePublished - Jan 26 2016



  • Atomic force microscopy
  • Carbon nanotube
  • Metrology
  • Microwave impedance microscopy
  • Quantum capacitance

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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