Surface studies of carbon-based ZnO nanocomposite films

The change in the surface and microstructural properties of pure diamond-like carbon (DLC) matrix when small quantities of ZnO were incorporated during deposition process was investigated in this paper. A 248 nm KrF Pulsed Laser Deposition (PLD) technique was used to fabricate these nanocomposite films. AFM showed that the ZnO grain sizes on the films increased with the increase of ZnO in the films, however, the overall film surfaces were still very smooth with RMS roughness <10 nm. XRD detected peaks at 2θ values of 34.4° and 36.4° indicated the presence of (0002) and (0101) planes of ZnO respectively confirming ZnO regions or clusters were present. High resolution XPS confirmed that ZnO and carbon compounds were present, and with an increase in ZnO, the carbon matrix showed a significant decrease in the sp³ content. 514 nm Raman spectroscopy confirmed XPS findings where a single broad peak gradually separated into two separate peaks in the region between 1100 cm−1 and 1700 cm−1 as the amount of ZnO increased. This suggested a transition in the microstructural properties of the carbon network from diamond-like (high sp³ content) to graphite-like (high sp² content).