  In this letter we present the results of systematic experimental
investigations of the effect of different chemical environments on the low
frequency resistance fluctuations of single layer graphene field effect
transistors (SLG-FET). The shape of the power spectral density of noise was
found to be determined by the energetics of the adsorption-desorption of
molecules from the graphene surface making it the dominant source of noise in
these devices. We also demonstrate a method of quantitatively determining the
adsorption energies of chemicals on graphene surface based on noise
measurements. We find that the magnitude of noise is extremely sensitive to the
nature and amount of the chemical species present. We propose that a chemical
sensor based on the measurement of low frequency resistance fluctuations of
single layer graphene field effect transistor devices will have extremely high
sensitivity, very high specificity, high fidelity and fast response times.
