Metrology
Many methods are available for measuring the size of particles suspended in a liquid. However, such techniques give only a statistical average of particle size. Detailed visualization and metrology of nano-particles is possible with traditional electron microscopy. However, SEM and TEM require sample preparation such as coating and microtoning. AFM allows the direct measurement of particle metrology. Sample preparation requires finding a substrate to which the particles naturally adhere. Below are images of two sizes of latex spheres measured with the AFM. The size of the particles can be directly measured with a line profile.   Figure 4: Image of 14 nm diameter colloidal gold spheres imaged with an AFM. The red line designates the line profile shown below. Image range is 4 µm × 4 µm.   Figure 5: Image of 28 NM colloidal gold spheres imaged with an AFM. The red line designates a line profile that is shown below. Image range is 4 µm × 4 µm.
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