Ca2+ detection utilising AlGaN/GaN transistors with ion-selective polymer membranes

Mohsen Asadnia, Matthew Myers, Gilberto A. Umana-Membreno, Tarun M. Sanders, Umesh K. Mishra, Brett D. Nener, Murray V. Baker, Giacinta Parish

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)
251 Downloads (Pure)


We demonstrate highly selective and sensitive potentiometric ion sensors for calcium ion detection, operated without the use of a reference electrode. The sensors consist of AlGaN/GaN heterostructure-based transistor devices with chemical functionalisation of the gate area using poly (vinylchloride)-based (PVC) membranes having high selectivity towards calcium ions, Ca2+. The sensors exhibited stable and rapid responses when introduced to various concentrations of Ca2+. In both 0.01 M KCl and 0.01 M NaCl ionic strength buffer solutions, the sensors exhibited near Nernstian responses with detection limits of less than 10-7 M, and a linear response range between 10-7-10-2 M. Also, detection limits of less than 10-6 M were achieved for the sensors in both 0.01 M MgCl2 and 0.01 M LiCl buffer solutions. AlGaN/GaN-based devices for Ca2+ detection demonstrate excellent selectivity and response range for a wide variety of applications. This work represents an important step towards multi-ion sensing using arrays of ion-selective field effect transistor (ISFET) devices.

Original languageEnglish
Pages (from-to)105-110
Number of pages6
JournalAnalytica Chimica Acta
Publication statusPublished - 22 Sept 2017


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