Reduction of 1/f Noise in Graphene after Electron-Beam Irradiation

We investigated the effect of the electron-beam irradiation on the level of the low-frequency 1/f noise in graphene devices. It was found that 1/f noise in graphene reveals an anomalous characteristic - it reduces with increasing concentration of defects induced by irradiation. The increased amount of structural disorder in graphene under irradiation was verified with micro-Raman spectroscopy. The bombardment of graphene devices with 20-keV electrons reduced the noise spectral density, S(I)/I^2 (I is the source-drain current) by an order-of magnitude at the radiation dose of 104 micro-C/cm^2. Our theoretical considerations suggest that the observed noise reduction after irradiation can be more readily explained if the mechanism of 1/f noise in graphene is related to the electron-mobility fluctuations. The obtained results are important for the proposed graphene applications in analog, mixed-signal and radio-frequency systems, integrated circuit interconnects and sensors.