Arsine gas sensor based on gold-modified reduced graphene oxide

Abstract

A gas sensor was developed for arsine (AsH3) which is the most toxic inorganic gas. The sensor was prepared from reduced graphene oxide (rGO), modified with a thin gold film, on an interdigitated array electrode. The conductance of the Au/rGO sensor was monitored in the presence of flowing AsH3 that was prepared by reduction of aqueous arsenite with borohydride and vaporization of the hydride. Gas sensors fabricated with only rGO or Au did not exhibit AsH3 sensitivity. However, rGO sensors combined with Au exhibited reversible conductivity enhancement with AsH3. The increase in conductivity probably occurred because the AsH3 depleted adsorbed oxygen on the Au islands, resulting in the enhancement of hole conduction in the rGO film. Responses were observed for sub-ppmv levels of AsH3. The amounts of gold and rGO, the GO reduction, and the operating temperature were optimized to obtain a detection limit of 0.01ppmv (determined from a signal level three times the baseline noise). Interference from other gases and vapors was examined. The sensor responded to NO2, but this is not expected to be present in air-quality-controlled clean rooms. AsH3 is one of the most toxic chemicals used in the semiconductor industry, and the Au/rGO-based AsH3 sensor is expected to have widespread applications.