2-Mercaptobutanedioic-Acid-Modified AlGaN/GaN High Electron Mobility Transistor With Folded Gate for Fe³⁺ Detection

A 2-mercaptobutanedioic acid modified enhancement-mode AlGaN/GaN high-electron-mobility transistor (HEMT) device with a 5-fold gate was proposed for Fe3+ specific detection. The crystal quality and surface morphology of the epitaxial material were characterized by X-ray diffraction and atomic force microscopy. The analysis of I-V characteristics and the current response of the device at a constant drain bias of 7 V show that the current response variation increased with an increase in Fe3+ concentration. Additionally, the sensitivity of the 5-fold-gate HEMT sensor was calculated, which was found to be greater. The current response results of the HEMT after adding multiple heavy metal ions proved that the sensor specifically recognizes Fe3+. Therefore, the 2-mercaptobutanedioic acid modified 5-fold gate HEMT sensor has great potential in the real-time detection of trace Fe3+.