Related Experiment Video
Updated: Aug 22, 2026

Fabrication of a Solution-gated Indium-Tin-Oxide-based One-piece Transistor Enabling Sensitive Biosensing
Published on: August 29, 2025
Gallium nitride-based potentiometric anion sensor
Nikos A Chaniotakis1, Yiannis Alifragis, Giorgos Konstantinidis
1Laboratory of Analytical Chemistry, Department of Chemistry, University of Crete, 71409 Iraklion-Crete, Greece. nikos@ chemistry.uoc.gr
Abstract:
The gallium nitride (GaN) semiconductor is used as the sensing element for the development of a potentiometric anion sensor. The anion recognition mechanism is based on the selective interaction of anions in solution with the epitaxial Ga-face polarity GaN (0001) wurtzite crystal film grown on sapphire. The native GaN crystal is used for the development of an ion blocked sensor. The potential is based on the Volta potential, generated at the semiconductor/solution interface and within the Helmholtz layer, due to specifically adsorbed anions. The selectivity of the sensor is based on the direct interaction of the anionic ligand with the outer electron-defective gallium atoms; thus, it is not dependent on the lipophilicity of the adsorbed charged species. The chemical resistivity of the GaN crystal provides sensors with excellent lifetime, signal stability, and reproducibility.
Related Concept Videos
Potentiometry: Membrane Electrodes
Potentiometry: Overview
Junction Potentials in Galvanic Cells
Potentiometry: Types of Electrodes
The Standard Hydrogen Electrode (SHE) is a widely used reference electrode that maintains zero potential across all temperatures. However, its need for a continuous hydrogen gas supply renders it impractical for everyday use.
An alternative to SHE is the Saturated Calomel Electrode (SCE). This electrode features an...
Gas Chromatography: Types of Detectors-II

