Electrical detection of trace zinc ions with an extended gate-AlGaN/GaN high electron mobility sensor

In this report, we have developed a high sensitivity zinc ion (Zn2+) detection method based on a Schiff base functionalized extended gate (EG)-AlGaN/GaN high electron mobility (HEMT) sensor. The complexation reaction between the Schiff base and the zinc ions would cause surface potential change on the extended gate, and achieve the purpose of zinc ion detection. Compared with conventional methods, the Schiff base functionalized EG-AlGaN/GaN high electron mobility sensor showed a rapid response (less than 10 seconds) and the limit of detection (LOD) was 1 fM. At the same time, the real-time detection of zinc ion concentration ranging from 1 fM to 1 μM showed good linearity (R2 = 0.9962). These results indicated that it provides a promising real-time detection method for trace-free zinc ion trace detection.