Terahertz sensing with carbon nanotube layers coated on silica fibers: carrier transport versus nanoantenna effects

Abstract

Carbon nanotube layers prepared as coatings on silica fibers are found to be suitable for terahertz detection in 0.5–7.3 THz range within temperatures of 4.2–70 K. In time-domain of terahertz excitation, two following constituents in the photoresponse are discriminated: the first one is attributed to the bolometric effect while the other one is related to the photoconductivity caused by the terahertz-induced hopping effect. In frequency domain, nonmonotonic behavior of the photoconductivity is associated with prevailing carbon nanotube-induced antenna effects in the electronic transport. The experimental observations are supported by theoretical estimates.