Over the last few months, we’ve been collaborating with Mike Leopold and his students in the chemistry department to use our atomic force microscope to image their nanoparticle films. We just purchased a small number of extra sharp (and extra expensive) tips for the microscope that allow us to resolve surface features about 1 nanometer in size. This image of a thin gold film that was coated over a mica surface is our first picture with the new tips. The mica is mostly very smooth, except for the big crevasse in the lower right hand corner. The surface roughness that you see is from the gold film, which clumps together to form small “grains” about 20-30 atoms across, or about 10 nanometers.
Take a moment to appreciate the scale of this picture. The vertical scale at the right shows that the darkest areas are about 5 nanometers lower than the whitest areas; most of the surface roughness is on the order of about two nanometers. The entire image is 500 nanometers across, or half a micron. If it shows up on your computer screen as 4 inches across, then the width of a human hair on the same scale would be about fifty feet!
This image was taken by my student, Nate Lawrence.