Dual-gated bilayer graphene hot electron bolometer

TL;DR

This paper presents a dual-gated bilayer graphene hot-electron bolometer capable of broadband infrared detection, demonstrating high sensitivity and fast response at cryogenic temperatures, with potential for various photonics applications.

Contribution

It introduces a tunable bandgap bilayer graphene bolometer that exploits hot-electron effects for high-speed, sensitive infrared detection at relatively high temperatures.

Findings

Achieved low noise equivalent power of 33 fW/Hz^{1/2}.

Demonstrated device speed >1 GHz at 10 K.

Confirmed large electron-phonon heat resistance aligns with theoretical models.

Abstract

Detection of infrared light is central to diverse applications in security, medicine, astronomy, materials science, and biology. Often different materials and detection mechanisms are employed to optimize performance in different spectral ranges. Graphene is a unique material with strong, nearly frequency-independent light-matter interaction from far infrared to ultraviolet, with potential for broadband photonics applications. Moreover, graphene's small electron-phonon coupling suggests that hot-electron effects may be exploited at relatively high temperatures for fast and highly sensitive detectors in which light energy heats only the small-specific-heat electronic system. Here we demonstrate such a hot-electron bolometer using bilayer graphene that is dual-gated to create a tunable bandgap and electron-temperature-dependent conductivity. The measured large electron-phonon heat resistance is in good agreement with theoretical estimates in magnitude and temperature dependence, and enables our graphene bolometer operating at a temperature of 5 K to have a low noise equivalent power (33 fW/Hz1/2). We employ a pump-probe technique to directly measure the intrinsic speed of our device, >1 GHz at 10 K.