Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene. uri icon

abstract

  • Terahertz radiation has uses in applications ranging from security to medicine. However, sensitive room-temperature detection of terahertz radiation is notoriously difficult. The hot-electron photothermoelectric effect in graphene is a promising detection mechanism; photoexcited carriers rapidly thermalize due to strong electron-electron interactions, but lose energy to the lattice more slowly. The electron temperature gradient drives electron diffusion, and asymmetry due to local gating or dissimilar contact metals produces a net current via the thermoelectric effect. Here, we demonstrate a graphene thermoelectric terahertz photodetector with sensitivity exceeding 10VW(-1) (700VW(-1)) at room temperature and noise-equivalent power less than 1,100pWHz(-1/2) (20pWHz(-1/2)), referenced to the incident (absorbed) power. This implies a performance that is competitive with the best room-temperature terahertz detectors for an optimally coupled device, and time-resolved measurements indicate that our graphene detector is eight to nine orders of magnitude faster than those. A simple model of the response, including contact asymmetries (resistance, work function and Fermi-energy pinning) reproduces the qualitative features of the data, and indicates that orders-of-magnitude sensitivity improvements are possible.

published proceedings

  • Nat Nanotechnol

altmetric score

  • 298.462

author list (cited authors)

  • Cai, X., Sushkov, A. B., Suess, R. J., Jadidi, M. M., Jenkins, G. S., Nyakiti, L. O., ... Fuhrer, M. S.

citation count

  • 423

complete list of authors

  • Cai, Xinghan||Sushkov, Andrei B||Suess, Ryan J||Jadidi, Mohammad M||Jenkins, Gregory S||Nyakiti, Luke O||Myers-Ward, Rachael L||Li, Shanshan||Yan, Jun||Gaskill, D Kurt||Murphy, Thomas E||Drew, H Dennis||Fuhrer, Michael S

publication date

  • January 2014