An international team of scientists constructs the first germanium-tin semiconductor laser for silicon chips
Scientists from Forschungszentrum Jülich and the Paul Scherrer Institute in Switzerland in cooperation with international partners have presented the first semiconductor consisting solely of elements of main group IV. As a consequence, the germanium-tin (GeSn) laser can be applied directly onto a silicon chip and thus creates a new basis for transmitting data on computer chips via light: this transfer is faster than is possible with copper wires and requires only a fraction of the energy. The results have been published in the journal Nature Photonics.
The transfer of data between multiple cores as well as between logic elements and memory cells is regarded as a bottleneck in the fast-developing computer technology. Data transmission via light could be the answer to the call for a faster and more energy efficient data flow on computer chips as well as between different board components. “Signal transmission via copper wires limits the development of larger and faster computers due to the thermal load and the limited bandwidth of copper wires. The clock signal alone synchronizing the circuits uses up to 30% of the energy – energy which can be saved through optical transmission,” explains Prof. Detlev Grützmacher, Director at Jülich’s Peter Grünberg Institute.
Some long-distance telecommunication networks and computing centres have been making use of optical connections for decades. They allow very high bandwidths even over long distances. Through optical fibres, signal propagation is almost lossless and possible across various wavelengths simultaneously: a speed advantage which increasingly benefits both micro- and nanoelectronics. “The integration of optical components is already well advanced in many areas. However, in spite of intensive research, a laser source that is compatible with the manufacturing of chips is not yet achievable,” according to the head of Semiconductor Nanoelectronics (PGI-9).
Future nanoelectronic information storage devices are also tiny batteries – astounding finding opens up new possibilities
Resistive memory cells (ReRAM) are regarded as a promising solution for future generations of computer memories. They will dramatically reduce the energy consumption of modern IT systems while significantly increasing their performance. Unlike the building blocks of conventional hard disk drives and memories, these novel memory cells are not purely passive components but must be regarded as tiny batteries. This has been demonstrated by researchers of Jülich Aachen Research Alliance (JARA), whose findings have now been published in the prestigious journal Nature Communications. The new finding radically revises the current theory and opens up possibilities for further applications. The research group has already filed a patent application for their first idea on how to improve data readout with the aid of battery voltage.
Conventional data memory works on the basis of electrons that are moved around and stored. However, even by atomic standards, electrons are extremely small. It is very difficult to control them, for example by means of relatively thick insulator walls, so that information will not be lost over time. This does not only limit storage density, it also costs a great deal of energy. For this reason, researchers are working feverishly all over the world on nanoelectronic components that make use of ions, i.e. charged atoms, for storing data. Ions are some thousands of times heavier that electrons and are therefore much easier to ‘hold down’. In this way, the individual storage elements can almost be reduced to atomic dimensions, which enormously improves the storage density.