The enormous progress in information technology is mainly related to the fact that the electronic parts in computers are getting smaller and smaller. And smaller automatically means quicker and cheaper. In the past forty years, the number of transistors in a computer chip has doubled every two years. However, in ten years from now we will reach a physical limit, estimates Trouwborst. At this limit, the basic principles of the transistor do not longer work properly.
If we want to continue with making faster computers, new methods have to be discovered. One possibility is to use atoms and molecules. Trouwborst’s fundamental research on electron transport through individual atoms and molecules fits into this hunt.
During the research, Trouwborst developed a new method to organize gold atoms in such a way that a very tiny mechanical switch could be made with them: only a single gold atom forms the contact. In addition, Trouwborst constructed a new type of electronic switch of the same miniscule size.
The method works with a so-called break junction. First, a gold wire is fixed onto a strip of flexible plastic. By now carefully bending the strip, the gold wire slowly stretches out, just like chewing gum. Just before it breaks, the wire has a diameter of only one gold atom. Extremely careful further bending (at the nanoscale) moves the ends a tiny distance away from each other. Although the wires are now separated, the fracture is is not definitive. As soon as it is very, very carefully bent back into position the ends fuse together again.
Contact of a single atom
Trouwborst repeated this bending back and forth for many times, in a very controlled way. Every time the wire breaks, the atoms in the two ends get organized in a different way. Trouwborst discovered that this reorganization gradually becomes more regular. Finally, the points look like carefully stacked pyramids of billiard balls with a single atom at the apex. ‘By moving the two ends back and forth by a distance of 0.1 nanometre, the switch can be turned on and off’, says Trouwborst.
Moreover, the system can also be used to ‘catch’ a molecule between the ends. That is useful for studying the electronic characteristics of that molecule. When an electrical voltage is set over the ends, all the electron transport goes through that single molecule in the middle.
Trouwborst used hydrogen molecules for his research. When increasing the voltage, the hydrogen molecule starts to vibrate between the ends of the gold threads. Trouwborst discovered that the resistance then suddenly changes, it jumps down. ‘You can simply turn the system on or off by making the molecules vibrate or not’, says Trouwborst. ‘This type of switch has never been shown before.’
Although related to the vibrating molecules, the exact cause of this switching behaviour is still unknown. Trouwborst suspects that is has something to do with a phase transition. More research is needed before the switches can actually be used. However, ‘what is clear’, says Trouwborst, ‘is that it provides new insight on the road to using molecules as functional building elements in the electronics of the future.’
Jos Speekman | alfa
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy