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

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

Research output: Contribution to journalArticleResearchpeer-review

308 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)814-819
Number of pages6
JournalNature Nanotechnology
Volume9
Issue number10
DOIs
Publication statusPublished - 1 Jan 2014

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