Structural Characteristics of Alumina Nanoparticles Synthesised by DC Reactive Sputtering Technique

In this work, Al2O3 nanoparticles were synthesized using the DC reactive sputtering technique. A highly pure aluminum target was sputtered within a gas mixture containing oxygen. The structural characteristics of the synthesized nanoparticles were introduced by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM). An inter-electrode distance of 4 cm can describe the operation parameters, Ar: O2 gas mixing ratio of 50:50, applied voltage of 1500 V and discharge current of 25 mA. The prepared samples showed a polycrystalline structure with an amorphous nature due to the formation of nanoparticles, which were approximately spherical with a minimum size of 21 nm and an average grain size of 40.7 nm. Some agglomerations were observed in the prepared samples. The elemental composition analysis revealed that the prepared material contains aluminum and oxygen with no traces of other elements. The stoichiometry and homogeneity of the prepared material were also shown. All functional groups corresponding to the vibrational modes of the Al2O3 molecule were confirmed. The energy band gap of the prepared nanomaterial was determined based on its absorption spectrum and measured to be 4.46 eV; this demonstrates a promising approach for producing highly pure metal oxide nanomaterial by the DC reactive sputtering technique.