Microwave detection and mixing in metallic single wall carbon nanotubes and potential for a new terahertz detector

Abstract

This paper reports measurements of microwave (up to 4.5 GHz) detection in metallic single-walled carbon nanotubes. The measured voltage responsivity was found to be 114 V/W at 77K and 9,000 V/W at 4.2K. We also demonstrated heterodyne detection at 1 GHz. Above 1.3 GHz the detector response falls off by 12 dB/ octave. The detection mechanism can be explained based on standard microwave detector theory and the nonlinearity of the DC IV-curve, the so-called "zero-bias anomaly". We discuss the possible causes of this nonlinearity. While the frequency response is limited by circuit parasitics in this measurement, we discuss evidence that indicates that the intrinsic effect is much faster and that applications of carbon nanotubes as terahertz detectors are feasible. Index Terms-terahertz detectors, single wall carbon nanotubes, microwave detectors, contact resistance.