# Highly Sensitive Room-Temperature Graphene-Modulated AlGaN/GaN HEMT THz Detector Architecture

## TL;DR

A new room-temperature THz detector using graphene and AlGaN/GaN HEMT structures is proposed, offering high sensitivity and broad bandwidth.

## Contribution

A novel THz detector architecture using graphene as a plasmon absorber for room-temperature operation is introduced.

## Key findings

- The detector achieves a responsivity of 2.12 × 10⁶ V/W at 1 THz.
- The design enables broadband THz detection with a 2 THz bandwidth at room temperature.
- Graphene's Drude absorption reduces phonon losses, enabling efficient THz detection.

## Abstract

This work proposes new architecture, supported by analytical modelling and computer-aided design (CAD) simulations, for a highly sensitive monolayer graphene-gated AlGaN/GaN HEMT terahertz (THz) detector operating at room temperature (RT). The monolayer graphene gate acts as a surface plasmon absorber for the incident THz radiation. The carrier density perturbation caused by incident THz energy on the monolayer graphene surface is then capacitively coupled to the two-dimensional electron gas (2DEG) channel of the HEMT structure underneath. The channel is partially depleted for increased mobility and nonlinearity with potential asymmetry across the channel for consistent photogeneration. The Drude absorption of THz radiation initiates intraband transitions in monolayer graphene, thereby reducing phonon losses. These reduced phonon losses enable RT THz detection. Based on our simulations, the proposed detector architecture can generate a responsivity of 2.12 × 106 V/W at 1 THz with a broadband bandwidth of 2 THz.