New feature for atomic force microscopy: Determination of chemical properties of atoms

Physicists in Japan, Spain and the Czech Republic have developed a new type of atomic force microscope (AFM - Atomic Force Microscope) that enables the identification of chemical characteristics of individual atoms. surface of a material.

This could be considered a leap of AFM compared to existing AFMs that can only detect the position of atoms.This device can identify local components and structures using an extremely accurate method of determination, which can even be used for manipulating each type of atom - a property that can allows building nanostructures to each atom (According to recent results in Nature 446 64, 2007).

Atomic force microscopy (AFM) was released more than 20 years ago in the eyes of scientists who are considered to be a great tool for examining atoms on the surface of both conductive and insulating materials. . This device works on the principle of using a probe (usually made of longitude) at the top of which an atom is vibrated and scanned across the surface of the material, based on the recognition of the interaction between the head This detector with surface atoms, scientists can rebuild the surface image of the material, from morphology to three-dimensional images of the surface. Although this device has the ability to distinguish different atoms, it has not allowed us to determine the chemical characteristics of atoms, and it is difficult to understand the atomic structure.

Operation principle of AFM.

Recently, Óscar Custance of Osaka University (Japan) and colleagues in Spain and the Czech Republic have shown that AFM can actually identify chemical characteristics if they know the basic components in advance. of material . This information gives us the relative content of atoms on the surface which correlates with where a single atom is located.

However, the key challenge for this step is the chemical affinity because the surface morphology is strongly dependent on the quality of the probe, there is no way to produce a single sign from an atom Characteristic writing (scientists call " fingerprints ") that are easily found in appropriate measurements.

Custance along with his team overcame this barrier by inventing an extremely sensitive adjustment method that can analyze in detail how the force acting on the probe changes compared to the distance given. with different atoms, and thus create a digital library of force-distance curves. Next, physicists correctly pinpointed the maximum suction force on each curve and compared them to find the relative value for each type of atom.

Results with different types of atoms.

Because relative values ​​do not depend on external parameters as detector probes, they can certainly provide atomic " fingerprints " to allow us to identify the surface characteristics of objects. Different materials. "The ability to analyze atomic characteristics at the surface can multiply the outstanding capabilities inherent in AFM" - Custance said.

Custance also told Physics Web that from work, one could even manipulate individual atoms, a technique that could be achieved before but could not be added to the ability to identify raw types. Different work, this work opens up applications in semiconductor fields, allowing engineers to produce higher quality components by transplating selected transistors in nanoscale sizes.

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