1,790 research outputs found
Low-noise top-gate graphene transistors
We report results of experimental investigation of the low-frequency noise in
the top-gate graphene transistors. The back-gate graphene devices were modified
via addition of the top gate separated by 20 nm of HfO2 from the single-layer
graphene channels. The measurements revealed low flicker noise levels with the
normalized noise spectral density close to 1/f (f is the frequency) and Hooge
parameter below 2 x 10^-3. The analysis of the noise spectral density
dependence on the top and bottom gate biases helped us to elucidate the noise
sources in these devices and develop a strategy for the electronic noise
reduction. The obtained results are important for all proposed graphene
applications in electronics and sensors.Comment: 9 pages, 4 figure
Modification of Graphene Properties due to Electron-Beam Irradiation
The authors report micro-Raman investigation of changes in the single and
bilayer graphene crystal lattice induced by the low and medium energy
electron-beam irradiation (5 and 20 keV). It was found that the radiation
exposures results in appearance of the strong disorder D band around 1345 1/cm
indicating damage to the lattice. The D and G peak evolution with the
increasing radiation dose follows the amorphization trajectory, which suggests
graphene's transformation to the nanocrystalline, and then to amorphous form.
The results have important implications for graphene characterization and
device fabrication, which rely on the electron microscopy and focused ion beam
processing.Comment: 13 pages and 4 figure
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