title: Mercury(II) selective sensors based on AlGaN/GaN transistors.
abstract: This work presents the first polymer approach to detect metal ions using AlGaN/GaN transistor-based sensor. The sensor utilised an AlGaN/GaN high electron mobility transistor-type structure by functionalising the gate area with a polyvinyl chloride (PVC) based ion selective membrane. Sensors based on this technology are portable, robust and typically highly sensitive to the target analyte; in this case Hg2+. This sensor showed a rapid and stable response when it was introduced to solutions of varying Hg2+concentrations. At pH 2.8 in a 10-2M KNO3ion buffer, a detection limit below 10-8M and a linear response range between 10-8M-10-4M were achieved. This detection limit is an order of magnitude lower than the reported detection limit of 10-7M for thioglycolic acid monolayer functionalised AlGaN/GaN HEMT devices. Detection limits of approximately 10-7M and 10-6M in 10-2M Cd(NO3)2and 10-2M Pb(NO3)2ion buffers were also achieved, respectively. Furthermore, we show that the apparent gate response was near-Nernstian under various conditions. X-ray photoelectron spectroscopy (XPS) experiments confirmed that the sensing membrane is reversible after being exposed to Hg2+solution and rinsed with deionised water. The success of this study precedes the development of this technology in selectively sensing multiple ions in water with use of the appropriate polymer based membranes on arrays of devices.
authors: School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009, Australia; Department of Engineering, Macquarie University, NSW 2109, Australia. Electronic address: mohsen.asadnia@mq.edu.au.
authors: Mohsen
authors: M
authors: Asadnia
authors: School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009, Australia; CSIRO Energy Flagship, Kensington, Western Australia 6151, Australia.
authors: Matthew
authors: M
authors: Myers
authors: School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009, Australia.
authors: N D
authors: ND
authors: Akhavan
authors: Department of Imaging and Applied Physics, Curtin University, Bentley, Western Australia 6102, Australia.
authors: Kane
authors: K
authors: O'Donnell
authors: School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009, Australia.
authors: Gilberto A
authors: GA
authors: Umana-Membreno
authors: Electrical and Computer Engineering Department, University of California, Santa Barbara, CA 93106, USA.
authors: U K
authors: UK
authors: Mishra
authors: School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009, Australia.
authors: Brett
authors: B
authors: Nener
authors: School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009, Australia.
authors: Murray
authors: M
authors: Baker
authors: School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009, Australia.
authors: Giacinta
authors: G
authors: Parish
keywords: AlGaN; Heavy metal detection; ISFET; Mercury; Polymer membrane