Thermoelectric graphene photodetectors with sub-nanosecond response times at Terahertz frequencies

TL;DR

This paper demonstrates room-temperature graphene-based THz photodetectors with sub-nanosecond response times and high sensitivity, suitable for ultrafast spectroscopy, imaging, and quantum applications across the 0.1-10 THz range.

Contribution

It introduces high-bandwidth, antenna-coupled graphene transistors with various architectures that operate efficiently across the entire THz spectrum at room temperature.

Findings

Response time below 500 ps at 3.4 THz

Noise equivalent power less than 120 pW/Hz^{1/2}

Operates effectively across 0.1-10 THz range

Abstract

Ultrafast and sensitive (noise equivalent power <1 nWHz-1/2) light-detection in the Terahertz (THz) frequency range (0.1-10 THz) and at room-temperature is key for applications such as time-resolved THz spectroscopy of gases, complex molecules and cold samples, imaging, metrology, ultra-high-speed data communications, coherent control of quantum systems, quantum optics and for capturing snapshots of ultrafast dynamics, in materials and devices, at the nanoscale. Here, we report room-temperature THz nano-receivers exploiting antenna-coupled graphene field effect transistors integrated with lithographically-patterned high-bandwidth (~100 GHz) chips, operating with a combination of high speed (hundreds ps response time) and high sensitivity (noise equivalent power <120 pWHz-1/2) at 3.4 THz. Remarkably, this is achieved with various antenna and transistor architectures (single-gate, dual-gate), whose operation frequency can be extended over the whole 0.1-10 THz range, thus paving the way for the design of ultrafast graphene arrays in the far infrared, opening concrete perspective for targeting the aforementioned applications.