Subterahertz electromagnetic wave generation in a randomly networked single-walled carbon nanotubes photoconductive switch

Abstract

We demonstrated an electromagnetic (EM) wave generation that reaches up to 250 GHz in the photoconductive switch based on randomly networked single-walled carbon nanotubes (SWNTs). Furthermore, we investigated the bias dependence of the electromagnetic wave amplitudes. This subterahertz radiation is generated by the acceleration of photogenerated carriers through fluctuation-induced tunneling in single-walled carbon nanotube bundles. Below the bias field of 20 kV/cm, the signal was enhanced with an increase in the bias field. However, the signal amplitudes decreased above 20 kV/cm due to emerging space-charge accumulation and scattering effect occurring at the defects and contact points. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773487]