CC BY
5Detectors of terahertz radiation based on 2D materials
K.V. Shein12, E. Zharkov3, A. Lyubchak12, P. Bondareva12, R. Izmaylov2, E. Baeva12, A. Kolbatova12, G.N. Goltsman1,2, I. Charaev4, D.A. Bandurin5, I. Gayduchenko12*
1-National Research University Higher School of Economics, Moscow, Russia, 101000 2- Moscow Pedagogical State University, Moscow, Russia, 119435 3- Programmable Functional Materials Lab, Brain and Consciousness Research Center, Moscow, Russia,
121205
4- University of Zürich, Zürich, Switzerland, 8057 5- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575
Recently terahertz range (THz) of EM spectrum has been of great interest due to a wide spectrum of potential applications: medical diagnostics, non-destructive testing, security systems, and observational astronomy. Hot-electron bolometers (HEBs) play a crucial role in a variety of such applications. The operation principle of such thermal detectors is based on the sensitivity of their resistance to the radiation-induced change in electronic temperature. One of the parameters limiting the sensitivity of such detectors is electronic heat capacity. While conventional superconducting HEBs are typically produced from sputtered Nb or NbN films, their thickness and quality are limited by the magnetron sputtering system, making it exceedingly difficult to achieve thicknesses in the nanometer range to reduce the electronic heat capacity.
In this work, we study alternative platform for this research based on layered van der Waals materials (vdW) owing to the simplicity of achieving few-layer thicknesses and low electronic heat capacity. First, we report the fabrication of superconducting HEBs out of few-layer NbSe2 microwires [1]. By improving the interface between NbSe2 and metal leads connected to a broadband antenna, we overcome the impedance mismatch between this vdW superconductor and the radio frequency (RF) readout circuitry that allowed us to achieve large responsivity THz detection over the range from 0.13 to 2.5 THz with minimum noise equivalent power of 7 pW/Hz05.
Next, we explore a novel approach to inventing graphene-based THz bolometers using noise thermometry. The heating of electrons caused by the absorption of THz radiation is detected by measuring noise spectral density in graphene devices. The potential advantages of this approach include high sensitivity, as well as the ability to easily multiplex detector signals, which allows the creation of detector arrays.
This work was financially supported by RSF (project No. 23-72-00014).
[1] K. Shein, et al, Fundamental Limits of Few-Layer NbSe2 Microbolometers at Terahertz Frequencies, Nano Letters, 24 (7), 2282-2288, (2024).
