Tunnel field-effect transistors for sensitive terahertz detection

Abstract

The rectification of electromagnetic waves to direct currents is a crucial process for energy harvesting, beyond-5G wireless communications, ultra-fast science, and observational astronomy. As the radiation frequency is raised to the sub-terahertz (THz) domain, ac-to-dc conversion by conventional electronics becomes challenging and requires alternative rectification protocols. Here, we address this challenge by tunnel field-effect transistors made of bilayer graphene (BLG). Taking advantage of BLG’s electrically tunable band structure, we create a lateral tunnel junction and couple it to an antenna exposed to THz radiation. The incoming radiation is then down-converted by the tunnel junction nonlinearity, resulting in high responsivity (>4 kV/W) and low-noise (0.2 pW/$$\sqrt{{\rm{Hz}}}$$ Hz ) detection. We demonstrate how switching from intraband Ohmic to interband tunneling regime can raise detectors’ responsivity by few orders of magnitude, in agreement with the developed theory. Our work demonstrates a potential application of tunnel transistors for THz detection and reveals BLG as a promising platform therefor.

Roadmap of Terahertz Imaging 2021

“…The current success, as well as further improvements of performance, are strongly related to the general development in the field of high-frequency integrated circuits and correlate with the maturity of technology. Furthermore, the introduction of novel twodimensional materials, such as graphene, allows involving additional mechanisms, such as carrier heating [162][163][164], ballistic transport [165], or tunneling currents [166], which might be exploited to enhance rectification properties.…”

Recent Progress in the Development of Graphene Detector for Terahertz Detection

“…The working principle of graphene zero-bias detector mainly includes a photovoltaic effect, photo-thermoelectric effect, plasma wave resonance, etc. [ 67 , 68 ]. Compared with conventional photodetectors, such as GaAs/AlGaAs devices, graphene-based detectors have a wider detection wave range and faster response speed [ 69 ].…”

“…This limitation has little effect on the responsivity of the detector and is easily overlooked. Bandurin et al [ 67 ] developed a tunnel field-effect transistor (TFET) model to rectify high-frequency signals. Since the thermoelectric plays a minor part in this scenario, the responsivity of the detector is governed by the responsivity of the channel and the tunnel junction.…”

Recent progress in terahertz modulation using photonic structures based on two‐dimensional materials

“…With the development of femtosecond lasers, plentiful of newly discovered or rediscovered THz generation and detection schemes have revitalized the THz technology. [4][5][6][7] Based on frequency conversion using nonlinear optics, these techniques are usually more reliable, straightforward, and potentially much less costly than the traditional approaches. 8,9 THz functional devices (e.g., modulators, 10 filters, 11 absorbers, 12 and sensors 13 ) are in high demand and have also attracted extensive researches besides THz generations and detections.…”