Carbon Nanotube Based Schottky Diodes as Uncooled Terahertz Radiation Detectors

Despite the intensive development of the terahertz technologies in the last decade, there is still a shortage of efficient room-temperature radiation detectors. Carbon nanotubes (CNTs) are considered as a very promising material possessing many of the features peculiar for graphene (suppression of backscattering, high mobility, etc.) combined with a bandgap in the carrier spectrum. In this paper, we investigate the possibility to incorporate individual CNTs into devices that are similar to Schottky diodes. The latter is currently used to detect radiation with a frequency up to 50 GHz. We report results obtained with semiconducting (bandgap of about 0.5 eV) and quasi-metallic (bandgap of few meV) single-walled carbon nanotubes (SWNTs). Semiconducting CNTs show better performance up to 300 GHz with responsivity up to 100 VW-1, while quasi-metallic CNTs are shown to operate up to 2.5 THz.