AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Tuesday Sessions
       Session NS-TuP

Paper NS-TuP20
Experimental Evidence of p-type Doping for Long Channel Carbon Nanotube Transistor

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Nanometer Scale Science and Technology Poster Session
Presenter: D. Kang, Samsung Advanced Institute of Technology, Korea
Authors: D. Kang, Samsung Advanced Institute of Technology, Korea
N. Park, Dankook University, Korea
B. Kim, Chonbuk National University, Korea
J. Kim, Chonbuk National University, Korea
W. Park, Samsung Advanced Institute of Technology, Korea
Correspondent: Click to Email
Carbon nanotubes(CNT) show dramatic changes in physical and chemical properties under different ambient conditions because of its high surface area. However, the possibility of p-type doping has been controversial for several years. While the thermoelectric power measurement obviously reported the oxygen-induced hole doping in the bundles of nanotubes, transport measurement with single short nanotube revealed that the adsorption effect lead to the work function change of the electrode, rather than the doping the nanotube body. However, in this study, we show that the doping effect would be prominent in the single nanotube transistor when the CNT is long(~5 µm). In order to decouple mixed effects from doping and metal work function change, we masked the interface (CNT/metal) and channel (CNT) region of CNT FET with conventional photoresists, respectively and measured Ids-Vg characteristics in air and vacuum. Preliminary data show that p-doping due to adsorption of ambient gas molecules could be possible and another critical factor to govern electrical properties of long channel CNT transistors. In addition, we observe that changes in Ids-Vg and Vth (threshold voltage) are associated with where it was masked.