Adv. Mater. http://doi.org/f3fpj5 (2015)

Black phosphorus (BP) — a two-dimensional material where the atoms are linked together in puckered sheets — is a promising material for making terahertz (THz) wave detectors due to its high hole mobility exceeding 650 cm2 V−1 s−1 and a very high on–off ratio of photo-induced current. Exploiting these advantages, Leonardo Viti and co-workers from Italy, USA, France and Poland have now demonstrated efficient room temperature THz photodetectors based on a FET that features integrated THz asymmetric antennas designed to enhance the sensitivity. Flakes of BP with thicknesses around 10 nm were mechanically exfoliated from BP crystals grown by chemical vapour transport. The FET device with a resonance frequency of 0.3 THz was fabricated by electron beam lithography and metal evaporation. THz waves in the frequency range of 0.26–0.38 THz were focused to the FET devices, which exhibited a maximum responsivity and noise-equivalent power of 0.15 V W−1 and 40 nW Hz−1/2, respectively.