Band Engineering of Partially Exposed Carbon Nanotube Field - Effect Transistors

Submitted for the MAR05 Meeting of The American Physical Society Band Engineering of Partially Exposed Carbon Nanotube FieldEffect Transistors XIAOLEI LIU, ZHICHENG LUO, SONG HAN, TAO TANG, DAIHUA ZHANG, CHONGWU ZHOU, University of Southern California — We present a new approach to engineer the band structure of carbon nanotube fieldeffect transistors via selected area chemical gating. By exposing the center part or the contacts of the nanotube devices to oxidizing or reducing gases, a good control over the threshold voltage and subthreshold swing has been achieved. Our experiments reveal that NO2 shifts the threshold voltage higher while NH3 shifts it lower for both centerexposed and contact-exposed devices. However, modulations to the subthreshold swing are in opposite directions for center-exposed and contact-exposed devices: NO2 lowers the subthreshold swing of the contact-exposed devices, but increases that of the center-exposed devices; In contrast, NH3reduces the subthreshold swing of the center-exposed devices, but increases that of the contactexposed devices. A model has been developed based on Langmuir isotherm, and the experimental results can be well explained. Xiaolei Liu University of Southern California Date submitted: 01 Dec 2004 Electronic form version 1.4