Oxygen-induced p-type doping of a long individual single-walled carbon nanotube

Abstract

The effect of oxygen adsorption on a nanotube-based field effect transistor have beencontroversial as to whether it induces p-type doping of the nanotube body or the work functionincrease in the metal electrode. Here we report a transport measurement showing that along individual single-walled nanotube can be doped as p-type upon oxygen adsorption. Wediscuss that, despite the fact that the charge transfer between the nanotube andO2 adsorbator has not been agreed to date, the effect of oxygen adsorption should still beinterpreted as inducing p-type doping in the nanotube body. The n-type doping byNH3 adsorption is also measured for the purpose of comparison. Based on these observations, wesuggest that, while the Schottky barrier management could be more effective for thetransistor with a short nanotube, the doping effect could be more influential in devices withlonger nanotubes.