Novel applications of carbon nanotube: Sensor, one-dimensional contact, and field-effect-transistor.

摘要

A single-walled carbon nanotube (SWNT) can be viewed as a graphene sheet rolled up into a seamless hollow cylinder. Since the discovery in 1991, carbon nanotube has aroused tremendous research efforts worldwide. They have well defined structure in the atomic scale, and are electrically stable, mechanically robust and chemically inert. They are seen as the building blocks for the next generation of electronic, optical, electrochemical, electromechanical devices in the nanometer scale. In this thesis, I will demonstrate that polyethyleneimine and nafion functionalization impart high sensitivity and selectivity to carbon nanotube gas sensor arrays. I will also describe the fabrication of the first SWNT quasi-one dimensional electrodes. The sharp quasi-1D geometry of the source (S) and drain (D) electrodes can facilitate the optimum gate control for transistors involving Schottky barriers (SB) at the contact (which is the case for organic field-effect-transistors). I will also discuss the hydrogenation and hydro-carbonation (etching) of SWNTs. The temperature, power, and diameter dependences of hydrogenation and hydro-carbonation were revealed. I will also demonstrate the selective plasma etching of metallic SWNTs. We found strong diameter dependence of the selectivity. In the diameter range of 1.4-1.8nm, metallic SWNTs can be effectively etched and removed by methane plasma treatment, while the semiconducting SWNTs will remain. This selective plasma etching method might be a key step for large scale SWNTs based field-effect-transistors manufacturing.