Hysteresis caused by water molecules in carbon nanotube field-effect transistors

Woong Kim, Ali Javey, Ophir Vermesh, Qian Wang, Yiming Li, Hongjie Dai

Research output: Contribution to journalArticlepeer-review

878 Citations (Scopus)


Carbon nanotube field-effect transistors commonly comprise nanotubes lying on SiO2 surfaces exposed to the ambient environment. It is shown here that the transistors exhibit hysteresis in their electrical characteristics because of charge trapping by water molecules around the nanotubes, including SiO2 surface-bound water proximal to the nanotubes. Hysteresis persists for the transistors in vacuum since the SiO 2-bound water does not completely desorb in vacuum at room temperature, a known phenomenon in SiO2 surface chemistry. Heating under dry conditions significantly removes water and reduces hysteresis in the transistors. Nearly hysteresis-free transistors are obtainable by passivating the devices with polymers that hydrogen bond with silanol groups on SiO 2 (e.g., with poly(methyl methacrylate) (PMMA)). However, nanotube humidity sensors could be explored with suitable water-sensitive coatings. The results may have implications to field-effect transistors made from other chemically derived materials.

Original languageEnglish
Pages (from-to)193-198
Number of pages6
JournalNano Letters
Issue number2
Publication statusPublished - 2003 Feb 1
Externally publishedYes

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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