The biosensor platform of graphene material has grown rapidly in the past few years due to their unique properties in electrical, thermal conductivity, large surface area, high fracture strength, high young modulus and biocompatibility. In this work, the chemically modified graphene oxide solutions were studied for electrical performance toward biosensor applications. The graphene oxide solutions were sprayed manually on top of silicon substrate at various temperatures of 100, 200 and 300 °C, respectively. Out of those temperatures, at 100 °C, the surface morphology of reduction graphene oxide showed a better performance in electrical measurement. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy were carried out to investigate the thermal reduction and the formation of graphene through surface morphology observation. Then a surface modification will conducted using APTES and electrical characteristic of the current-voltage (i-v) were performed.