Characterization of graphene electrode on nickel thin film for electrochemical sensing

In this work, chemical vapor deposited (CVD) graphene on sputtered nickel thin film using acetylene as a carbon source is characterized for electrochemical sensing applications. Nickel catalyst was deposited by magnetron sputtering on SiO₂/Si substrate. Graphene was grown under the flow of 3/24 sccm acetylene/hydrogen at a pressure of 0.4 Torr and a temperature of 700°C for 1 minute. Characterizations by scanning/transmission electron and atomic force microscopy show that synthesized graphene film has multiple layers with very smooth surface and high degree of crystallinity. Raman spectra further confirm graphene structure with relatively high and sharp 2D peak compared to graphite. The electrochemical sensing performance of graphene electrode is evaluated for detections of potassium iodide by cyclic voltammetry. The graphene/nickel electrode exhibits highly pronounced redox peaks at 0.4 V, 0.55 V and 0.8 V while nickel electrode show no apparent redox peak. Thus, the presence of CVD graphene film greatly enhances electrochemical performance of Ni electrode.