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

doi:10.1016/j.aca.2017.07.066

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

Anal Chim Acta. 2017 Sep 22:987:105-110. doi: 10.1016/j.aca.2017.07.066. Epub 2017 Aug 7.

Authors

Mohsen Asadnia¹, Matthew Myers², Gilberto A Umana-Membreno³, Tarun M Sanders³, Umesh K Mishra⁴, Brett D Nener³, Murray V Baker⁵, Giacinta Parish⁶

Affiliations

¹ School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Perth, WA 6009, Australia; Department of Engineering, Macquarie University, NSW 2109, Australia.
² School of Molecular Sciences, The University of Western Australia, 35 Stirling Hwy., Perth, WA 6009, Australia; CSIRO Energy Flagship, Kensington, WA 6151, Australia.
³ School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Perth, WA 6009, Australia.
⁴ Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, USA.
⁵ School of Molecular Sciences, The University of Western Australia, 35 Stirling Hwy., Perth, WA 6009, Australia.
⁶ School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Perth, WA 6009, Australia. Electronic address: giacinta.parish@uwa.edu.au.

PMID: 28916033
DOI: 10.1016/j.aca.2017.07.066

Abstract

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.

Keywords: AlGaN/GaN; Calcium detection; Chemical sensor; Ion selective field effect transistor.