Adsorption of Oxygen Molecules on Individual Carbon Single-walled Nanotubes

TL;DR

This study investigates how oxygen molecules adsorb on individual semiconducting single-walled carbon nanotubes at room temperature, affecting their electrical resistance through physisorption and Fermi level pinning.

Contribution

It provides new insights into the physical adsorption mechanism and electronic effects of oxygen on single-walled carbon nanotubes at ambient conditions.

Findings

Oxygen adsorption is physisorption.

Resistance increases by ~100 times without O2.

Fermi level pinning causes sensitive response.

Abstract

Our study of the adsorption of oxygen molecules on individual semiconductiong single-walled carbon nanotubes at ambient conditions reveals that the adsorption is physisorption, that the resistance without O2 increases by ~two orders of magnitude as compared to that with O2, and that the sensitive response is due to the pinning of the Fermi level near the top of the valence band of the tube resulting from impurity states of O2 appearing above the valence band.