The influence of substrate temperature on the structure and optical properties of NiO thin films deposited using the magnetron sputtering in the layer-by-layer growth regime

Abstract

Vanadium oxide (VO x ) thin films are promising materials, exhibiting electrical, optical, and mechanical properties highly tunable by processing and structure. This work uniquely applying atomic force microscopy (AFM) nanoindentation correlated with X-ray diffractometry and Raman spectroscopy structural analysis to investigate the intricate connections between VO x post-annealing, phase composition, and resulting nanoscale mechanical functionality. Utilizing an ultra-sharp diamond tip as a nanoscale indenter, indentation is performed on VO x films with systematic variations in structure – from mixed insulating oxides to VO 2 -dominated films. Analytical modeling enables extraction of hardness and elastic modulus with nanoscale resolution. Dramatic mechanical property variations are observed between compositions, with order-of-magnitude increases in hardness and elastic modulus for the VO 2 -rich films versus insulating oxides. Ion implantation further enhances nanomechanical performance through targeted defect engineering. Correlating indentation-derived trends with detailed structural and morphological characterization elucidates explicit structure-property relationships inaccessible by other techniques. The approach provides critical mechanics-driven insights into links between VO x synthesis, structure evolution, and property development. Broader implementation will accelerate processing optimization for electronics and advanced fundamental understanding of nanoscale structure-functionality relationships