title: Understanding the electrolyte background for biochemical sensing with ion-sensitive field-effect transistors.
abstract: Silicon nanowire field-effect transistors have attracted substantial interest for various biochemical sensing applications, yet there remains uncertainty concerning their response to changes in the supporting electrolyte concentration. In this study, we use silicon nanowires coated with highly pH-sensitive hafnium oxide (HfO(2)) and aluminum oxide (Al(2)O(3)) to determine their response to variations in KCl concentration at several constant pH values. We observe a nonlinear sensor response as a function of ionic strength, which is independent of the pH value. Our results suggest that the signal is caused by the adsorption of anions (Cl(-)) rather than cations (K(+)) on both oxide surfaces. By comparing the data to three well-established models, we have found that none of those can explain the present data set. Finally, we propose a new model which gives excellent quantitative agreement with the data.
authors.affiliation: Department of Physics, University of Basel, Basel, Switzerland. alexey.tarasov@unibas.ch
authors.forename: Alexey
authors.initials: A
authors.lastname: Tarasov
authors.forename: Mathias
authors.initials: M
authors.lastname: Wipf
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Stoop
authors.forename: Kristine
authors.initials: K
authors.lastname: Bedner
authors.forename: Wangyang
authors.initials: W
authors.lastname: Fu
authors.forename: Vitaliy A
authors.initials: VA
authors.lastname: Guzenko
authors.forename: Oren
authors.initials: O
authors.lastname: Knopfmacher
authors.forename: Michel
authors.initials: M
authors.lastname: Calame
authors.forename: Christian
authors.initials: C
authors.lastname: Schönenberger
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003198:Computer Simulation; D004573:Electrolytes / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008956:Models, Chemical; D012825:Silicon / Q000737:chemistry*; D014173:Transistors, Electronic
chemical_list: D004573:Electrolytes; D012825:Silicon