Mpp 31120 10

The surface topography and architecture were analyzed using an Innova scanning probe microscope (Bruker, USA). Scans were performed in tapping mode under ambient temperature and pressure conditions, using silicon cantilevers (MPP-31120-10, Veeco, USA.) with a spring constant of 0.9 N m⁻¹ and a resonance frequency of approximately 20 kHz. Scanning was performed perpendicular to the axis of the cantilever at a scan speed of 1 Hz. Initially, 2.5 × 2.5 µm² areas were analyzed to evaluate the overall homogeneity of the surface, prior to generating topographical profiles at five different locations on each bSi surface.
High-resolution electron micrographs of the bSi surfaces were recorded using a field-emission scanning electron microscope (FE-SEM; ZEISS SUPRA 40 VP, Oberkochen, BW, Germany) at 3 kV under 10,000×, 30,000×, 70,000×, and 110,000× magnification using the method described in our previously published studies [1 (link), 2 (link)]. The nanopillared patterns present on the bSi surfaces were analyzed using ImageJ^® software package using a fast Fourier transform (FFT) algorithm [24 (link), 25 (link)]. The average FFT images are obtained by averaging over FFT transformed tiles of 512 × 512 pixels fitting into SEM images at 10,000× magnification with displacements of 100 pixels to each other.

All AFM scans were conducted using an Innova scanning probe microscope (Veeco, U.S.A.). Scans were performed in tapping mode at ambient temperature and pressure, using silicon cantilevers (MPP-31120-10, Veeco, U.S.A.) with a spring constant of 0.9 N m^-1 and a resonance frequency of approximately 20 kHz. Scanning was performed perpendicular to the axis of the cantilever at a scan speed of 1 Hz. Initially, 10 μm × 10 μm fields of view were scanned in order to identify suitable analysis regions of the surface, prior to analysis at higher resolution. Scan areas were selected to closely match with the resolution of electron micrographs, as the distance between individual sampling points can affect the calculated roughness parameters (Brune et al., 1997 ; Crawford et al., 2012 (link)).