Influence of substrate orientation on the morphologyand orientation of LaNiO₃ thin films

LaNiO₃ thin films were successfully prepared by a chemical method from citrate precursors. The LNO precursor solution was spin-coated onto Si (100) and Si (111) substrates. To obtain epitaxial or highly oriented films, the deposited layers were slowly heated in a gradient thermal field, with a heating rate of 1° min⁻¹, and annealed at 700°C. The influence of different substrate orientations on the thin film morphology was investigated using atomic force microscopy and X-ray diffraction analysis. Well-crystallized films with grains aligned along a certain direction were obtained on both substrates. Films deposited on both substrates were very smooth, but with a different grain size and shape depending on the crystal orientation. Films deposited on Si (100) grew in the (110) direction and had elongated grains, whereas those on Si (111) grew in the (211) direction and had a quasi-square grain shape.