Spatially resolved electrostatic potential and photocurrent generation in carbon nanotube array devices

Michael Engel, Mathias Steiner, Ravi S. Sundaram, Ralph Krupke, Alexander A. Green, Mark C. Hersam, Phaedon Avouris

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


We have used laser-excited photocurrent microscopy to map the internal electrostatic potential profile of semiconducting single-walled carbon nanotube (S-SWCNT) array devices with a spatial resolution of 250 nm. The measurements of S-SWCNTs on optically transparent samples provide new insights into the physical principles of device operation and reveal performance-limiting local heterogeneities in the electrostatic potential profile not observable with other imaging techniques. The experiments deliver photocurrent images from the underside of the S-SWCNT-metal contacts and thus enable the direct measurement of the charge carrier transfer lengths at the palladium-S-SWCNT and aluminum-S-SWCNT interfaces. We use the experimental results to formulate design rules for optimized layouts of S-SWCNT-based photovoltaic devices. Furthermore, we demonstrate the external control of the electrostatic potential profile in S-SWCNT array devices equipped with local metal gates.

Original languageEnglish (US)
Pages (from-to)7303-7310
Number of pages8
JournalACS nano
Issue number8
StatePublished - Aug 28 2012
Externally publishedYes


  • nano-optics
  • nanoelectronics
  • self-assembly

ASJC Scopus subject areas

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


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