Electronic nose for toxic gas detection based on photostimulated core–shell nanowires

Abstract

A novel fabrication of microelectronic nose based on ZnO nanowires and ZnO surface modifications including ZnO–ZnAl₂O₄ core–shell nanowires and ZnO–Zn₂TiO₄ core–shell nanowires gas-sensing elements operated at room temperature is reported. By combining vapor-phase transport processes and atomic layer deposition techniques, highly homogeneous core–shell nanowires structures can be successfully obtained on large scale areas. Under ultraviolet illumination of the specific oxide surfaces, photo-stimulated oxygen species (O₂⁻(ads)) respond to and dominate the gas sensing mechanism of the core–shell nanowires at room temperature. Principal component analysis results show the perfect discrimination of gases including toxic gases and non-toxic gases. This novel device can be used to identify both gas types with concentrations in the ppb level at room temperature.