Asylum research mfp 3d sa afm

AFM surface topography images
were acquired by an Asylum Research MFP-3D SA AFM (Oxford Instruments,
United Kingdom). Gwyddion software was used to process and analyze
the AFM topography images.^{39 (link)}

The overall
thickness of anodic
silicon oxide and GO was characterized at three different positions
on each sample (triplicate) using static angle ellipsometry at a wavelength
of 632.8 nm and an incidence angle of 70° (SE400, Sentech, Germany).
Both the overall layer thickness and the refractive index were used
as fitting parameters and average values with standard deviations
were calculated accordingly. Static (80°) and angle-resolved
(0°–80° between the sample and detector) X-ray photoelectron
spectra were measured (XPS, JPS-900 JEOL, Japan) to evaluate the chemical
composition of each surface. The element concentrations on the surfaces
of the individual sample sets were averaged and the standard deviations
were calculated accordingly. SEM images of the top surface (2000 and
10 000×) and the cross section (350 000×)
were taken using 2 kV acceleration voltage (SEM, Magellan 400, FEI,
USA). Atomic force microscopy (AFM) surface topography images were
acquired by an Asylum Research MFP-3D SA AFM (Oxford Instruments,
United Kingdom). A sharp knife was used to scratch the surfaces. The
scratched surfaces were rinsed with water.