Mobility in semiconducting carbon nanotubes at finite carrier density.
Carbon nanotube field-effect transistors operate over a wide range of electron or hole density, controlled by the gate voltage. Here we calculate the mobility in semiconducting nanotubes as a function of carrier density and electric field, for different tube diameters and temperatures. The low-field mobility is a nonmonotonic function of carrier density and varies by as much as a factor of 4 at room temperature. At low density, with increasing field the drift velocity reaches a maximum and then exhibits negative differential mobility, due to the non-parabolicity of the band structure. At a critical density, rho(c) approximately 0.35-0.5 electrons/nm, the drift velocity saturates at around one-third of the Fermi velocity. Above rho(c), the velocity increases with field strength with no apparent saturation.
Perebeinos
Vasili
V
IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598, USA. vperebe @us.ibm.cim
Tersoff
J
J
Avouris
Phaedon
P
D004574:Electromagnetic Fields; D004583:Electrons; D009038:Motion; D036103:Nanotechnology / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010316:Particle Size; D012212:Rheology; D012666:Semiconductors; D012680:Sensitivity and Specificity; D013499:Surface Properties; D013696:Temperature
D037742:Nanotubes, Carbon