Overcoming Piezo Scanner Limitations
Piezo scanners are used in atomic force microscopy (AFM). This type of scanning can be performed at a very high resolution. There are AFM techniques that can be used for almost every force interaction that can be measurable. While AFM is not useful under all circumstances, there are several reasons you should consider using this process.
The AFM Tip
AFM relies on a tip, a sample, and the force that is measured between both. The tip swings freely at the end of a cantilever. The tip is so small that it is measured by a few nanometers. The tip moves to the surface of the sample being measured. As the tip becomes dull or contaminated, technicians simply replace it with a new one.
One of the greatest advantages of AFM is that unlike with the electron microscope, the AFM is able to produce a 3D surface profile. The sample examed with an AFM does not require a special treatment.
The microscope can operate in environments that an electron microscope cannot operate in. For instance, while an electron microscope requires a vacuum, AFM can produce a surface profile in an ambient or liquid environment.
Scanning Area Size Limitations
An AFM has limitations with the scanning area size. For this reason, you may need to use parallel probes and use a technique similar to millipede data storage.
Scanning Speed Limitations
Electron microscopes are able to scan faster than AFM. While this might be inconvenient, given the greater capabilities of AFM, this is a good trade-off. Also, while AFM cannot scan at real-time, even when electron microscopes scan in real time, the image produced is low quality.
One technology that has been developed to overcome the slower speed of AFM is videoAFM. This is a fast-acting design that is actually faster than an electron microscope. This technique eliminates thermal drift, which could interfere with the ability of the AFM to measure distances between features on the object being scanned.
Image Artifact Concerns
All imaging devices can produce image artifacts that can reduce the quality of the image. Image artifacts cannot be completely avoided with any imaging device, including AFM. However, they can be reduced by properly handling the sample, by scanning on a smoother surface and by not scanning too fast. This will reduce the risk of the tip wearing, which will reduce the number of image artifacts. But when these limitations are overcome, your laboratory will produce much better images.