Gas sensing by flicker noise in Au-decorated graphene layers modulated by plasmonic resonance

Flicker noise can be utilized for enhanced gas sensing by the sensors made of graphene flakes decorated with Au nanoparticles. Gas molecules adsorb-desorb near Au nanoparticles and generate low-frequency noise components – a separate Lorentzian or local change in power spectral density. Flicker noise can be observed in gas sensors due to relatively low resistance and high bias current exposing resistance fluctuations in graphene flakes. Au nanoparticles modify the observed flicker noise because of ambient gas molecules' continuous adsorption-desorption processes. This effect can be modulated by plasmonic resonance phenomena in Au nanoparticles when irradiated by adequate light wavelengths. The plasmonic resonance phenomena induce additional charge within Au nanoparticles, which can be transferred into the graphene layer. The charge transfer process depends on the ambient atmosphere around the irradiated nanoparticle, which can be utilized for gas sensing. We present some experimental results and theoretical considerations of how this process can be enhanced to improve gas sensing by flicker noise measurements and analysis, considering its intensity and slope versus frequency.