Chemical Interactions of Nano Islandic Graphene Grown on Titanium Dioxide Substrates by Chemical Vapor Deposition

In this work, direct growth of graphene is carried out on TiO2 (110) substrates by chemical vapor deposition. For few device applications, it is convenient to grow graphene directly on the dielectric substrates rather than metal foil to minimize transfer and surface interface defects. Raman spectrum support graphene growth on TiO2 substrate by exhibiting D and G peaks. Graphene covered the whole TiO2 substrate with few areas where higher growth of carbon atoms occurs. The contrast of SEM images clearly showed the non-homogeneous growth at some places on substrate. EDX showed the presence of carbon % for the graphene grown TiO2 (graphene-TiO2) substrate which is further supported by the atomic percentage of carbon obtained by XPS. XPS shows a shift of 0.36 eV in Fermi edge for the graphene-TiO2 as compared to bare heated TiO2 substrate which supports carbon interaction with TiO2. Atomic force microscope further provides the 3D view of graphene layers obtained on TiO2. The average height of graphene layers lies in 5-10 nm range and the size of uniform patches of same height lies in 200-600 nm range. The wide coverage of graphene obtained on TiO2 supports direct growth method for dielectrics, however, to obtain the uniform thickness over the whole substrate is still challenging.

Automated summary

Graphene was directly grown on TiO2 substrates using chemical vapor deposition. Characterization techniques including Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy were employed to analyze the graphene-TiO2 samples. The results demonstrated the wide coverage of graphene on TiO2, but achieving uniform thickness throughout the substrate remains challenging.