Definition Atomic force microscope
Atomic force microscope is and instrument or a device which is used for imaging in different areas of work. It is very useful because it can image all types of surfaces including polymers, ceramics, composites, glass and biological samples. AFM was constructed to overcome the draw backs of STM (Scanning Tunneling Microscope) to diversify the dimensions of imaging and patterning.
Historical Background & Invention
Atomic Force Microscope was developed 2 decades ago by Binnig, Quate, and Gerber in 1985. The AFM that they constructed was consisted of a strip of gold foil and diamond shard attached with the strip. The attached diamond tip was able to contact the surface directly with the help of interaction mechanism. At present many new technologies contributed in modifying the original AFM to enjoy the better results.
How AFM works ( Atomic force microscope )
At present most of the atomic force microscopes uses laser for their deflection system, the laser beam is reflected back to the AFM lever and on the position sensor. Then the tips with micro fabrications and, with the radius from 10 nm, works at their turn for the imaging. This deflection technique was discovered by Meyer and Amer.
Based on the fact that AFM uses the forces between the tip and surfaces, these central forces have great significance for proper imaging This force is not calculated directly. But calculated by knowing the deflection of the lever, and the hardness of the cantilever. Or we can say that we should know the force and at which point lever would bend.
Modes of AFM
Atomic force microscope is considered to be dynamic and versatile and because of these unique properties it is applicable in the many research areas and also experienced different kind of modifications and changes in its structure and functioning. Every time it is used of the specific application and has different structure according to situation. Many mode of AFM are
available but the most commonly used are.
Non contact mode.
Contact AFM Mode
The very first and important operation mode of AFM is contact mode, contact mode is widely used in many applications. As the AFM tip is scanned along the sample surface, it gets deflected gradually as it moves over the surface. In consistent force mode, the tip is constantly adjusted again and again properly to maintain deflection and surface height too. In some scenarios the AFM tip is allowed to scan without proper adjustment, and one can easily measures the deflection. These are very useful, compact and efficient atomic revolutionary scans and are mostly known as variable deflections mode
Another important mode of Atomic Force microscope is Noncontact mode. This mode belongs to the family of AC modes, which refers to the utilization of an oscillator lever. A strong cantilever is oscillated in the attractive way, meaning that the tip is very close to the sample surface, but remains untouched to the surface. The forces present between the tip and sample are quite low power. The deflection is based on the frequency of resonance and amplitude of cantilever in non contact mode.
Examples of AFM systems
The most commonly used AFM systems are Nanosurf AFM systems these are easy to use, and ideal modified form of original AFM. Different kind f application models of AFM are present in the market having unique functional capabilities and properties. such as Nanites or automated atomic force microscopes which are programmable and contains moor in it, similarly, easy scan 2 ATM+ STM. Multi functional and multi purpose AFM which is used in many applications.