Silicon carbide (4H-SiC) is the ideal semiconductor material for power electronics. For instance, efficient power converters for electric vehicles or photovoltaic systems can be produced - as well as electronics that work at high temperatures. Until now, however, very few electron devices made of silicon carbide are on the market.
The reason for this: The quality of the crystals and epitaxial layers is not yet sufficient for the demanding applications because even the slightest material defects, in form of dislocations, can lead to a malfunction of the component. Dislocations are deviations from the ideal crystal lattice structure, which may occur in different types.
In his thesis project, „Structural defect characterization of 4H-SiC substrates and epitaxial layers using x-ray topography and x-ray diffractometry," Sebastian Polster of the Fraunhofer Institute for Integrated Systems and Device Technology IISB studied these dislocations. He compared the type and number of these crystalline defects using x-ray images that he recorded with the ANKA synchrotron source, with images that were prepared using the conventional etching technique in the laboratory. In this manner, he succeeded in depicting the limits of the established characterization method. The results of this method can now be interpreted with certainty. This is an important basis in order to improve the material regarding the avoidance of critical dislocation types in the material, so that electron devices based on SiC can dominate their market. In recognition of his accomplishments, Sebastian Polster is awarded the 2nd Hugo Geiger Prize.
Growing through holes
An important objective of solar cell research is to produce photovoltaic modules inexpensively, in order to make the power it produces competitive with conventional energy resources. One potential concept to achieve this is the use of crystalline thin-film solar cells, which come from a very thin layer of the expensive, ultrapure silicon. Another option can be found in solar cells whose current-collecting contacts are situated only on the back side of the solar cells, laden with via holes.. Physicist Nils Brinkmann of the Fraunhofer Institute for Solar Energy Systems ISE showed in his thesis project, „Epitaxy through holes: Process development and characterization," how the advantages of both varieties can be brought together.
One decisive factor in the new cell concept: minute via holes. The epitaxial layers grow through these on both sides of the thin silicon substrate. This completely new approach was developed by Nils Brinkmann with the aid of Simulations that he then applied in a production process. In addition, he showed how the degree of efficiency of the new solar cells can be further optimized. Nils Brinkmann is awarded the 3rd Hugo Geiger Prize.
Sebastian Polster | Fraunhofer Mediendienst
Thanks for the memory: NIST takes a deep look at memristors
22.01.2018 | National Institute of Standards and Technology (NIST)
Let the good tubes roll
19.01.2018 | DOE/Pacific Northwest National Laboratory
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
22.01.2018 | Materials Sciences
22.01.2018 | Earth Sciences
22.01.2018 | Life Sciences