Perpustakaan Digital ITB

We report our study in bilayer graphene field effect transistor, where the graphene films grown by using mechanical exfoliation method on SiO2/Si substrate. To realize the field effect transistor configuration, we perform the masking process and contact deposition after we verified the sample by optical microscopy and Raman spectroscopy. In masking process, we used 4 μm diameter tungsten (W) wire as mask and attached over graphene surface mechanically using glue, scotch tape, and tweezer. Electrical contact for drain and source in our device is fabricated by gold evaporation method where the Cr/Au (100 nm/ 300nm) metal stacks are deposited as source and drain electrodes. We measured the I-V curve of bilayer graphene transistor with the gate width (w) and length (l) of 4 μm and 5 μm respectively, and its transfer characteristic by applying back gate voltage. We observed the resistivity of bilayer graphene is 2.67 × 10-6 Ωm, which is in the range of resistivity of the graphite and acceptable result since it has interspace connection between each layers. The observation of n-type and p-type transitions verifies the ambipolar characteristic and low gate modulation. The hole and electron mobility were extracted to be μh = 1408 cm2/Vs and μe = 156 cm2/Vs respectively. We observed that the maximum and minimum drive current at Vd = 600 mV are 85 μA and 62 μA, yielding 1.37 on/off current ratio.