Decoration of graphite nanoplatelets with Nb2O5 deposited by radio frequency sputtering
Abstract
The depositions of various nano-materials onto graphite nanoplatelets (layers of graphene) are ideal for different applications. Deposition by radio frequency (RF) sputtering technique can degrade layers of graphene due to interaction of high energy sputtered particles and plasma species. By optimizing the deposition parameters, the level of damage to graphene layers can be controlled. In this scenario, niobium pentaoxide (Nb2O5) thin films deposited on graphite nanoplatelets (GNPs) powder by various deposition parameters like RF power, process pressures, deposition time and sample vibration frequency in argon atmosphere. The structural properties of the samples were investigated by X-ray diffraction (XRD) and Raman spectroscopy. For the chemical analysis of the samples X-ray photoelectron spectroscopy (XPS) was used. The interlayer d spacing of the GNPs calculated from the XRD pattern changes with Nb2O5. By increasing Nb2O5 contents through deposition parameters, defects on the surface of GNPs increased and basal planes of GNPs gradually loss their initial ordering, decreasing the degree of graphitization. Raman study revealed that both doping and strain contributed shift of G and 2D bands to lower wave numbers in the Raman spectra. From the XPS analysis, we found that, with increasing RF power, low process pressure and increasing sample vibration frequency more Nb2O5 contents are and intercalated into GNPs system.