Subband population in a single-wall carbon nanotube diode

TL;DR

This paper demonstrates current rectification in a single-wall carbon nanotube diode with impurity-induced diode behavior, showing control over subband occupation via electrostatic doping at low temperature.

Contribution

It reveals how impurity placement in a nanotube can create diode behavior and how subband occupation can be electrically controlled.

Findings

Rectification observed in nanotube diode due to impurity.

Step-wise current increase with gate voltage at 77K.

Control over subband occupation through electrostatic doping.

Abstract

We observe current rectification in a molecular diode consisting of a semiconducting single-wall carbon nanotube and an impurity. One half of the nanotube has no impurity, and it has a current-voltage (I-V) charcteristic of a typical semiconducting nanotube. The other half of the nanotube has the impurity on it, and its I-V characteristic is that of a diode. Current in the nanotube diode is carried by holes transported through the molecule's one-dimensional subbands. At 77 Kelvin we observe a step-wise increase in the current through the diode as a function of gate voltage, showing that we can control the number of occupied one-dimensional subbands through electrostatic doping.