What is the Atomic Force Microscopes Contribution to Nanotechnology?
Measurement
An atomic force microscope (AFM) creates a highly magnified three dimensional image of a surface. The magnified image is generated by monitoring the motion of an atomically sharp probe as it is scanned across a surface. With the AFM it is possible to directly view features on a surface having a few nanometer-sized dimensions including single atoms and molecules on a surface. This gives scientists and engineers an ability to directly visualize nanometer-sized objects and to measure the dimensions of the surface features.
With an atomic force microscope it is possible to measure more than the physical dimensions of a surface. This is because there is a "physical" interaction of the probe with a surface. An example is that by lightly pushing against a surface with the probe, it is possible to measure how hard the surface is. Also the ease by which the probe glides across a surface is a measure of the surface "friction".
Modification
Just as a pen is used for writing on a paper's surface, it is possible to write on a surface with an atomic force microscope. This new type of "lithography" results in a completely new method for making surface modifications at the nanometer scale. It is already possible to modify surfaces by physically scratching the surface, by directly depositing molecules on a surface, and by using electric fields to modify surfaces. Presently the use of the AFM is in a very exploratory phase, but showing tremendous promise. One of the important technological issues that must be solved is the writing speed of the AFM lithography systems.
Manipulation
With an AFM probe it is possible to directly move objects across a surface. The objects may be pushed, rolled around, or even picked up by the probe. With such methods it is possible to create nanometer sized objects. One of the important aspects of using an AFM for direct manipulation is the user interface that is used for generating the motions of the probe. There are interfaces that measure the locations of a particle, such as microspheres on a surface, and then automatically move the spheres into a pre-established location. In another type of interface, called the nanomanipulator,
the motion of the probe follows the motion of your hand. When you move your hand up and down, the probe moves up and down. Such an interface also allows users to "feel" and "touch" a surface.
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