Oral Presentation

Graphene-based hot electron bolometers with Johnson noise thermometry

Author(s): Feiming Li, Wei Miao, Qianghui Luo, Zheng Wang, Wen Zhang, Yuan Ren, Kangmin Zhou, Jiaqiang Zhong, and Shengcai Shi

Presenter: Feiming Li (Purple Mountain Observatory, Chinese Academy of Sciences, China)

Graphene hot-electron bolometer (HEB) detectors, with weak electron–phonon interaction and a wide working temperature range, are of particular interest for terahertz (THz) applications including astronomy. In this paper, we report on the performance of a zero-biased THz HEB detector using Johnson noise thermometry based on bilayer graphene (BLG) of high charge carrier density. Two BLG HEB devices with respective normal-metal and superconducting electrodes are compared particularly for their thermal conductance and detection sensitivity (noise equivalent power, NEP) in a low-temperature regime (0.3–10 K). With electron out-diffusion largely suppressed by Andreev reflection, the device with superconducting electrodes outperforms the device with normal-metal electrodes, giving an electrical NEP of 15 fW/Hz^0.5
and a dynamic range of 47 dB at 0.3 K. Moreover, its optical coupling efficiency is found to be 58% and can reach as high as 92% with the optical losses of the measurement system calibrated out. Graphene detectors of this kind can achieve better detection performance given lower readout noise and decreased electron–phonon thermal conductance.