Direct electrochemical response of glucose at nickel-doped diamond like carbon thin film electrodes

Ni-doped diamond like carbon (NiDLC) thin films were deposited on Si substrates by cosputtering a pure Ni target with different DC powers (10, 20, 30, and 40 W) and a pure graphite target with a DC power of about 650 W at room temperature. X-ray photoelectron spectroscopy (XPS) was used to measure the chemical composition and binding energy of the NiDLC thin films, and the C bonding structures of the films were also measured with micro-Raman spectroscopy. The XPS and Raman results illustrated that the fraction of sp2-hybridized C bonds increased with increased Ni concentration in the films. The surface roughness of the NiDLC thin films also increased with increased Ni concentration as measured with atomic force microscopy (AFM). The NiDLC thin films were used as working electrodes to sense the direct electrochemical response of glucose in 0.1 M NaOH aqueous solutions with different glucose concentrations. The results showed that the NiDLC film electrodes with different Ni concentrations had varying reaction behavior to glucose.