All InN/InGaN solid-state potentiometric chloride sensor with super Nernstian sensitivity

Abstract

Abstract We demonstrate an all-solid-state potentiometric sensor constructed from solid-state InN/InGaN sensing- and reference electrodes with the epitaxial InN/InGaN layers directly grown on Si substrates. The sensor, evaluated in KCl aqueous solution, exhibits super-Nernstian sensitivity of −78 mV/decade with good linearity for concentrations of 0.01–1 M, which is the physiologically relevant range. Good stability and re-usability are demonstrated by a long-time drift below 0.2 mV h−1 and standard deviation of 8 mV for repeated measurements over 10 d. These properties fulfil the requirements for compact, robust and highly sensitive all-solid-state sensors and sensor arrays.