Direct and heterodyne detection of microwaves in a metallic single wall carbon nanotube

This letter reports measurements of microwave (up to 4.5GHz) detection in metallic single walled carbon nanotubes. The measured voltage responsivity was found to be 114V∕W at 77K. The authors also demonstrated heterodyne detection at 1GHz. The detection mechanism can be explained based on standard microwave detector theory and the nonlinearity of the dc IV curve. The authors discuss the possible causes of this nonlinearity. While the frequency response is limited by circuit parasitics in this measurement, the authors discuss evidence that indicates that the effect is much faster and that applications of carbon nanotubes as terahertz detectors are feasible.