Flicker Noise in Bilayer Graphene Transistors

We present results of the experimental investigation of the low-frequency noise in bilayer graphene transistors. The back-gated devices were fabricated using the electron beam lithography and evaporation. The charge neutrality point for the transistors was around +10 V. The noise spectra at frequencies f > 10-100 Hz were of the 1/f type with the spectral density on the order of S₁ ~ 10^-23-10^-22 A²/Hz at the frequency of 1 kHz. The deviation from the 1/f spectrum at f < 10-100 Hz suggests that the noise is of the carrier-number fluctuation origin due to the carrier trapping by defects. The Hooge parameter was determined to be as low as ~ 10^-4. The gate dependence of the normalized noise spectral density indicates that it is dominated by the contributions from the ungated parts of the device and can be reduced even further. The obtained results are important for graphene electronic and sensor applications.