Volatile organic compounds sensor with stacked interdigitated electrodes coated with monolayer-protected gold nanoclusters

In this paper we present a complementary metal-oxide-semiconductor (CMOS) based volatile organic compounds (VOCs) sensor featured by stacked interdigitated electrodes and a polysilicon microheater. N-octanethiol functionalized gold nanoparticles (Au-C8), a type of monolayer-protected gold nanoclusters (MPCs), were employed as sensing material. The design of the sensor and the fabrication utilizing a commercial CMOS process were demonstrated. MPCs were coated by airbrushing MPCs suspension and simultaneous heating was provided by the on-chip microheater. The sensor performance was tested using octane, toluene and butanol. The responses were fast, and the sensitivity, defined as the ratio of resistance change rate (ppm) to gas concentration (ppm), was 33.1, 27.6 and 21.9 ppm/ppm for octane, toluene and butanol, respectively. Being a universal detector implicated its applicability to a gas chromatograph.