Nanoscale stereometric analysis of polycrystalline PDI8-CN2 thin films on hydrogen-terminated silicon (H-Si) for enhanced surface functionality

In this study, polycrystalline thin films of PDI8-CN2 deposited on hydrogen-terminated silicon (H-Si) were thoroughly examined using atomic force microscopy (AFM). The research focused on characterizing the surface micromorphology through advanced analyses, including contour line plots, Abbott-Firestone curves, furrow depth analysis, texture direction evaluation, power spectral density (PSD), frequency spectrum, fractal analysis, and motif analysis. The contour line plots revealed significant height variations, while the Abbott-Firestone curve mapped the relative proportions of elevated and recessed areas. Furrow depth analysis showed prominent valleys with a mean depth of 7.03 nm. Texture direction analysis indicated an isotropy of 32 %, confirming moderate surface directionality. The PSD analysis revealed a dominant wavelength of 2834 nm, aligning with the roughness features observed. Fractal analysis demonstrated a self-similar surface with a fractal dimension of 2.45. Motif analysis indicated significant contributions of peaks and pits to surface roughness, with peaks having the largest mean area of 0.220 μm². Statistical parameters, including a root mean square height of 5.02 nm and maximum height of 42.4 nm, confirmed the roughness and height variation. Integrating of these techniques offers a detailed understanding of surface topography, which is essential for optimizing functional properties in material applications. The results provide insight into the structural organization of PDI8-CN2 films, which is important for optimizing their use in organic electronics.