In this work, graphene oxide (GO) and reduced graphene oxide (rGO) based field effect transistor (FET) with substrate gate and channel length variation has been designed and fabricated for biosensor application. Initially, graphene oxide (GO) and reduced graphene oxide (rGO) were synthesized using improved hummers method and water based thermal reduction respectively. Then, the produced GO and rGO were coated onto FET with various channel length (300 µm, 400 µm and 500 µm). Scanning electron microscopy (SEM) results show that rGO produced more compact structure and huge folded curtain as compare to GO sample. Besides, the interlayer spacing of rGO was in between graphite and GO. Furthermore, fourier-transform infrared (FTIR) results indicated that most of the oxygenated functional groups in GO was reduced after thermal reduction process. For capacitance frequency curve (Cf) test, the curve shows that the FET decrease in capacitance with increase in channel length. Overall, our study establishes a correlation between structural and electrical properties of GO and rGO with channel length variation.
