Ethanolamine Modified ZnO Nanorods-Based Disposable Gate-AlGaN/GaN High Electron Mobility Transistor for pH Sensing

In this paper, a pH sensor based on disposable gate-AlGaN/GaN high electron mobility transistor was proposed, where ethanolamine modified ZnO nanorods was functionalized as sensing membrane. Different from those reported before that molecular modifications were utilized as sensing probes, disposable gate with functionalized ZnO nanorods possesses higher sensitivity and better stability. Moreover, ethanolamine modified on ZnO nanorods could provide highly reproducible homogeneous and dense monolayer-coating with amines, which not only protect ZnO from being dissolved in acidic and alkaline solutions and enables the sensor conduct pH detection in a wider range, but also promotes the sensitivity of the pH sensor. The physical and pH sensing characteristics has been investigated. These results demonstrate the new proposed disposable gate-AlGaN/GaN HEMT pH sensor a promising pH sensor for practical application.