title: Al2O3/silicon nanoISFET with near ideal nernstian response.
abstract: Nanoscale ISFET (ion sensitive field-effect transistor) pH sensors are presented that produce the well-known sub-nernstian pH-response for silicon dioxide (SiO(2)) surfaces and near ideal nernstian sensitivity for alumina (Al(2)O(3)) surfaces. Titration experiments of SiO(2) surfaces resulted in a varying pH sensitivity ∼20 mV/pH for pH near 2 and >45 mV/pH for pH > 5. Measured pH responses from titrations of thin (15 nm) atomic layer deposited (ALD) alumina (Al(2)O(3)) surfaces on the nanoISFETs resulted in near ideal nernstian pH sensitivity of 57.8 ± 1.2 mV/pH (pH range: 2-10; T = 22 °C) and temperature sensitivity of 0.19 mV/pH °C (22 °C ≤ T ≤ 40 °C). A comprehensive analytical model of the nanoISFET sensor, which is based on the combined Gouy-Chapman-Stern and Site-Binding (GCS-SB) model, accompanies the experimental results and an extracted ΔpK ≈ 1.5 from the measured responses further supports the near ideal nernstian pH sensitivity.
authors.affiliation: BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
authors.forename: Songyue
authors.initials: S
authors.lastname: Chen
authors.forename: Johan G
authors.initials: JG
authors.lastname: Bomer
authors.forename: Edwin T
authors.initials: ET
authors.lastname: Carlen
authors.forename: Albert
authors.initials: A
authors.lastname: van den Berg
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D049329:Nanostructures / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D014173:Transistors, Electronic
chemical_list: D012822:Silicon Dioxide; D000537:Aluminum Oxide