Again, available from many microscope suppliers. Not to be used for apex determination using above formula. Array of Spheres Instead of individual spheres, construct an array. Any range of sizes. Not to be used for apex determination using above formula.
Sources See above.
Fabricated structures Sharp spikes provide direct image of AFM tip. Often, very little deconvolution is required. Assorted range of heights. Ken Westra et al. These are different from the structures above in that here the top portion is flat and not rounded.