Multifractal spectra of atomic force microscope images of Cu/Fe nanoparticles based films thickness

•We presented results from thin film surfaces at one deposition thickness of Cu and three of Fe.•We characterized the micromorphology of thin films synthesised by (DC) magnetron sputtering.•We used atomic force microscopy and multifractal geometry.•We determined the generalized dimension Dq.•We determined the singularity spectrum f(α) of the multifractal structure.

This paper analyses the thickness influence of Fe on Cu nanoparticles (NPs) synthesised by Direct-current (DC) magnetron sputtering on the three-dimensional (3-D) surface morphology of thin films.The thin films with Cu nanoparticles were deposited on glass substrates then; Fe nanoparticles were added to Cu ones. These nanostructures were investigated at one deposition thickness of Cu and three of Fe (Cu 55 nm, Cu 55 nm/Fe 40 nm, Cu 55 nm/Fe 55 nm, and Cu 55 nm/Fe 70 nm as thin films’ thickness), by means of X-ray diffraction, atomic force microscopy (AFM) and multifractal analysis, in order to evaluate the structure and relation among the 3-D micro-textured surface.The 3-D morphology of surface samples exhibits multifractal features characterized by nano-irregularities of various orders of size and different local densities spread on the surface. The local and global scale properties of 3-D surface geometry were quantitatively estimated using the generalized dimension Dq and the singularity spectrum f(α). The non-uniformity of the nano-irregularities are correlated with the generalized dimension Dq and the spectrum width Δα (Δα = αmax − αmin) of the multifractal spectra f(α).Multifractal approach in correlation with the surface statistical parameters are a sensitive and reliable tool for quantifying the thickness influence of Fe on Cu nanoparticles (NPs) synthesised by Direct-current (DC) magnetron sputtering on the 3D surface morphology of thin films.