Deposition and characterization of 1D RuO₂ nanocrystals by reactive sputtering

Well-aligned 1D RuO₂ nanocrystals (NCs) have been grown on sapphire (SA)(1 0 0), SA(0 0 1) and LiNbO₃ (LNO)(1 0 0) substrates via reactive magnetron sputtering using a Ru metal target. The surface morphology, structural and spectroscopic properties of the as-deposited NCs are characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and micro-Raman spectroscopy (RS). FESEM micrographs show that NCs grown on SA(1 0 0)/LNO(1 0 0) are vertically aligned, while NCs grown on SA(0 0 1) show in-plane alignment with mosaic structure. The XRD results indicate that the NCs are (0 0 1) and (1 0 0) oriented on SA(1 0 0)/LNO(1 0 0) and SA(0 0 1) substrates, respectively. A strong substrate effect on the alignment of the RuO₂ NCs deposition has been observed and the probable mechanism for the formation of these NCs has been discussed. The usefulness of the Raman spectroscopy as a structural characterization technique of NCs has been demonstrated.