Size-dependent electrical transport in CdSe nanocrystal thin films

Moon Sung Kang, Ayaskanta Sahu, David J. Norris, C. Daniel Frisbie

Research output: Contribution to journalArticlepeer-review


Electrical transport in films of CdSe nanocrystals with diameters varying from 2.9 to 5.1 nm was examined over 233-300 K by employing electrolyte gating to control the electron density. The transport parameters varied strongly and systematically with nanocrystal diameter. First, a strong correlation was observed between the device turn-on voltage and the size-dependent position of the lowest unoccupied electronic states of the nanocrystals. Second, the electron mobility increased with increasing particle diameter and reached a high value of 0.6 cm2/(V s) for films with 5.1 nm nanocrystals. Third, the charge transport could be described in terms of the nearest-neighbor-hopping mechanism with a size-dependent activation energy and a pre-exponential factor for mobility. The activation energy can be viewed as a size-dependent charging energy of an individual nanocrystal. Collectively, the combination of size- and temperature-dependent measurements provides a powerful approach to understanding electrical transport in nanocrystal films.

Original languageEnglish (US)
Pages (from-to)3727-3732
Number of pages6
JournalNano Letters
Issue number9
StatePublished - Sep 8 2010


  • CdSe nanocrystals
  • electrical transport
  • ion-gel gate dielectric
  • size dependence
  • thin-film transistors

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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