A novel “coral” carbon microprobe with and without N 2 incorporation

Abstract

“Coral”-type microstructure carbon films, with and without N 2 incorporation, were grown on sharpened tungsten microprobes by plasma enhanced chemical vapor deposition (PECVD) using H 2/CH 4/N 2 and H 2/CH 4 gas mixtures, respectively. The electrochemical behaviors of the coral-type carbon coated tungsten microprobe, characterized by various concentrations of ferrocyanide in a background of 0.1 M KCl, show excellent structural stability with similar microstructure before and after prolonged analysis without the need of surface pretreatment. The microprobes exhibit quasi-reversible kinetics with high signal-to-noise S/ B ratio. The N 2 incorporated microprobe shows a slightly wider potential window, no surface adsorption of the analyte and higher sensitivity as compared to the sample without nitrogen incorporation. Furthermore, the wide potential window of ∼ 3 V is very good as compared to boron-doped diamond electrodes which are ∼ 3.5 V. This well behaved; broad electrochemical behavior and the simple fabrication method make the “coral” carbon film microprobe an excellent candidate for electrochemical sensing.