Broadband detection of mid-infrared (IR) photons extends to advanced optoelectronic applications such as imaging, sensing, and telecommunications. While graphene offers an attractive platform for broadband visible/IR photodetection, previous efforts to improve its responsivity, for example, by integrating light-absorbing colloids or waveguide or antenna fabrication, were achieved at the cost of reduced photon detection bandwidth. In this work, we demonstrate room-temperature operation of a novel mid-IR photodetector based on a graphene-Bi2Se3 heterostructure showing broadband detection and high responsivity (1.97 and 8.18 A/W at mid- and near-IR, respectively), in which simultaneous improvement of the spectral range and responsivity is achieved via exploiting broadband absorption of mid-IR and IR photons in a small-band-gap Bi2Se3 topological insulator and efficient hot carrier separation and strong photogating across the Bi2Se3/graphene interface. With sufficient room for further improvement by interface engineering, our results show a promising route to realize ultrabroadband, high-responsivity hot-carrier optoelectronics at room temperature.
Bibliographical noteFunding Information:
J.K., S.P., S.S., S.C., C.I., J.P., J.L., M.N., and H.C. were supported by the National Research Foundation of Korea (NRF) through the government of Korea (MSIP) (Grant Nos. NRF-2015R1A2A1A10052520, NRF-2016R1A4A1012929), and Global Frontier Program (2014M3A6B3063709). J.S. and M.J. were supported by Institute for Basic Science (IBS), Korea, under the Project Code IBS-R014-G1-2016-a00. D.K. was supported by the Basic Science Research Program through the NRF funded by the Ministry of Science, ICT and Future Planning (Grant No. NRF-2015R1C1A1A02037430). S.C. and M.H. were supported by the Nation Research Foundation of Korea (NRF) through the government of Korea (MSIP) (Grant No. NRF-2016R1A4A1012929). N.K., M.S., J.M., and S.O. are supported by the National Science Foundation of the USA (DMR-1308142 and EFMA-1542798) and the Gordon and Betty Moore Foundation?s EPiQS Initiative (GBMF4418).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering