Graphene-Insulator-Superconductor junctions as thermoelectric bolometers

TL;DR

This paper proposes a graphene-insulator-superconductor thermoelectric bolometer that directly converts input power to voltage, characterized through numerical simulations showing promising sensitivity and response time for cosmological applications.

Contribution

It introduces a novel superconducting thermoelectric bolometer design based on G-I-S junctions, with detailed thermal modeling and noise analysis.

Findings

Noise Equivalent Power ~4×10^{-17} W/√Hz

Response time ~200 ns

SNR=1 in ~100 μs for 10^{-13} W input

Abstract

We design a superconducting thermoelectric bolometer made of a Graphene-Insulator-Superconductor tunnel junction. Our detector has the advantage of being passive, as it directly transduces input power to a voltage without the need to modulate an external bias. We characterize the device via numerical simulation of the full nonlinear thermal dynamical model of the junction, considering heating of both sides of the junction. While estimating noise contributions, we found novel expressions due to the temperatures of both sides being different than the bath temperature. Numerical simulations show a Noise Equivalent Power ${\rm NEP}\sim 4\times 10^{-17}\,{\rm W}/\sqrt{\rm Hz}$ for an input power of $\sim10^{-16}\,{\rm W}$, a response time of $\tau_{th}\sim 200\, {\rm ns}$ and an integration time to obtain a Signal-to-Noise Ratio ${\rm SNR}=1$ of $\tau_{\rm SNR=1}\sim 100\,\mu{\rm s}$ for an input power $\sim 10^{-13}\,{\rm W}$. Therefore, the device shows promise for large-array cosmological experiment applications, also considering its advantages for fabrication and heat budget.