Once Shed Through - Threefold Information Gain

Physicists develop new measuring method for active nanoscale components

No matter how big cell phones or computers are - the function of such electronic devices depends above all on the interaction of different materials. Therefore, both engineers and scientists need to know exactly how certain chemical elements behave within a computer chip or a diode or a transistor, and what happens when they connect with each other. Physicists at the Friedrich Schiller University of Jena have now developed a new method by which they receive several pieces of information simultaneously from the inside of a nanoscale component - while it is in the active state. The Jena scientists and their partners report on their findings in the current issue of the journal Science Advances.

"With our method, we can simultaneously retrieve information about the composition of the elements, their relationship to each other, their oxidation state, the nature of their bonding, and their internal electrical fields. " Prof. Dr. Carsten Ronning from the University of Jena. " These are all elementary indicators of the function of the component, " said the head of the project. However, in the approach that the physicists in Jena have developed together with colleagues from Grenoble, Madrid and Vienna, the components to be examined need not be elaborately prepared or possibly even destroyed. "In fact, we could scan the diodes of a powered cell phone without it getting damaged, "says Ronning.

X-ray from the particle accelerator

The decisive factor for the research approach is a very thin X-ray, with which the physicists from Jena first used a component specially made for their experiments. " We have introduced arsenic and gallium atoms into a silicon wire about 200 nanometers thick, which agglomerate by heating at one point, ie they aggregate together, creating a functional component, " explains Prof. Ronning. " Then we drove the wire along with a x-ray beam measuring 50 nanometers thick and irradiated it piece by piece."The scientists discovered that the elemental mixture transformed the X-rays - just like a solar cell - into electricity, which - like a diode - only flowed in one direction, so the scientists made the internal electric fields necessary for the function of the In addition, the component emitted light. " The X-rays radiate the atoms in the component and in turn emit characteristic radiation, " explains Dr. Andreas Johannes, who carried out the experiments. " This gives us a spectrum, that gives us valuable information about the individual elements and their relationship to each other."If one varies the energy of the incident X-rays, then spectra arise that allow statements about the oxidation state of the elements - and thus about the compounds per se.

Only new method allows this information gain by a measurement

"All this information through a measurement can be obtained so far only by our method, " says Andreas Johannes. Although there are comparable possibilities in the field of electron microscopy, the components would have to be specially prepared and possibly destroyed, since the penetration depth of the electron beam is much lower. In addition, such measurements could only take place in a vacuum - the X-ray method, however, is almost independent of a specific environment.

So far, such fine X-rays can only produce particle accelerators, which is why the Jena physicists have worked closely with the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, to develop the new measurement method. These facilities are available to both science and industry, so that existing components can be examined more closely and, above all, new combinations of materials can be tried out in order to obtain more efficient components. " Our method can, for example, provide valuable services in the development of new batteries, " says Andreas Johannes. " Because they also want to investigate researchers especially in operation and fully functional, for example, to read out the oxidation states of the elements.