Comparison of functionalized AlGaN/GaN HEMT sensor for the detection of various heavy metal ions

We report and compare a sensitive heavy metal ion sensor for copper ion (Cu2+), iron ion (Fe3+), lead ion (Pb2+) and cadmium ion (Cd2+) detection. The sensor consists of AlGaN/GaN high electron mobility transistor (HEMT) with L-cysteine functionalized active region on the gate. The sensor exhibits fast and stable response after the introduction of various heavy metal ions ranging from 0 mg/L to 20 mg/L to combine with the modifier to form stable complexes. The current response of the HEMT device shows a related behavior that decreases with increasing concentration of introduced heavy metal ions. Furthermore, the AlGaN/GaN HEMT-based sensor exhibited high sensitivities of 92.32 µA/(mg/L), 760.22 µA/(mg/L), 137.05 µA/(mg/L) and 63.63 µA/(mg/L) for the detection of Cu2+, Fe3+, Pb2+ and Cd2+, respectively. Therefore, the proposed functionalized AlGaN/GaN HEMT device displays potential in the application of efficient, fast and convenient detection of heavy metal ions.