Hooge’s constant for carbon nanotube field effect transistors

The $1∕f$ noise in individual semiconducting carbon nanotubes (s-CNT) in a field effect transistor configuration has been measured in ultrahigh vacuum and following exposure to air. The amplitude of the normalized current spectral noise density is independent of source-drain current and inversely proportional to gate voltage, to channel length, and therefore to carrier number, indicating that the noise is due to mobility rather than number fluctuations. Hooge’s constant for s-CNT is found to be $(9.3\pm 0.4)\times {10}^{-3}$ The magnitude of the $1∕f$ noise is substantially decreased by exposing the devices to air.