Dependence of Carbon Nanotube Field Effect Transistors Performance on   Doping Level of Channel at Different Diameters: On/off current ratio
  Choosing a suitable doping level of channel relevant to channel diameter is considered for determining the carbon nanotube field effect transistors' performance which seem to be the best substitute of current transistor technology. For low diameter values of channel the ratio of on/off current declines by increasing the doping level. But for higher diameter values there is an optimum point of doping level in obtaining the highest on/off current ratio. For further verification, the variations of performance are justified by electron distribution function's changes on energy band diagram of these devices. The results are compared at two different gate fields. 
Shaahin G. Shirazi, and Sattar Mirzakuchaki
cond-mat.mes-hall