How does a multiwalled carbon nanotube atomic force microscopy probe affect the determination of surface roughness statistics?

Through statistical analysis of atomic force micrographs of sputtered-silicon films, we examine the determination of surface roughness parameters, and how this determination is affected by probe characteristics, such as sharpness and aspect ratio. We compare values for the roughness exponent, α, and the lateral correlation length, ξ, calculated from micrographs obtained with multiple standard atomic force microscopy (AFM) probes in contact and noncontact modes, as well as from micrographs obtained with a multiwalled-nanotube-enhanced AFM probe. The sharper, lower-aspect-ratio nanotube probe is expected to provide a truer picture of the roughness parameters for these films. Using the nanotube probe, we obtained α=0.61±0.02, as compared to α∼0.83 obtained with conventional probes. We have also found the nanotube probe is able to detect a smaller lateral correlation length compared to that of the conventional AFM probes.