▎ 摘　　要

This work demonstrates a graphene/AlGaN/GaN sensing device with two-dimensional electron gas (2DEG) to-ward nitrogen dioxide (NO2), tetrahydrofuran, and acetone detection under UV light irradiation. We propose combining measurements of the DC characteristics with a fluctuation-enhanced sensing method to provide insight into the gas detection mechanisms in the synergistic structure of highly stable GaN and gas-sensitive graphene. Both DC and low-frequency noise studies reveal the impact of UV irradiation (275 nm) on the GaN-based field-effect transistor (FET). Gas detection improves under UV light with higher differentiability be-tween selected concentrations of inorganic (NO2) gas and the possibility of discrimination between weakly adsorbing organic species (tetrahydrofuran and acetone). Time-domain experiments confirm the stability and reversibility of sensor (short-time and long-time) responses and reduced time drift after employing UV light. Features observed in the 1/f noise spectra may indicate the high impact of the irradiation on the trapping states in the GaN-based heterostructure, which further modulates the fluctuations of the channel carriers in our device. Our findings broaden the view on AlGaN/GaN heterostructures modulated with a graphene gate for gas sensing purposes, including strongly binding inorganic gas and weakly adsorbing organic species.