MUNICH, Germany Carbon nanotubes are discussed as a future alternative to silicon-based transistors, but some material properties have turned out as an obstacle to industrial implementations. Now Danish and German researchers came up with an alternative to the alternative: Molybdenum sulfide has similar properties as carbon nanotubes minus its drawbacks.
Carbon nanotubes are on the agenda of many researchers since they feature excellent semiconducting properties. For this reason, technologists hope to be able to replace silicon transistors and memories in the long run by carbon nanotubes. However, drawbacks such as their tendency to stick together hitherto have prevented their industrial breakthrough. Besides sticking together, it is extremely difficult to apply electric contacts to them.
Researchers from the Univerity of Aarhus (Denmark), the Dresden Technical University and the Rossendorf Research Center (FZD) have been able to characterize molybdenum sulfide. The results which have been achieved both by experiments as well as by quantum mechanical simulation showed that the material which in the macro world is used as a lubricant in nano dimensions exposes very interesting properties from the perspective of semiconductor technology: Molybdenum sulfide nano particles for wires. When twisted, the wires turn conductivity on or off, thus they could be used as electric nano switches.
The reason for this effect is that the band gap of the material is proportional to its twisting angle, explained FZD researcher Sibylle Gemming in a statement. In addition to the switching properties, the molybdenum sulfide wires are easy to provide with an electric contact, and they have excellent electric conductivity which makes it easier to integrate the devices into microelectronic products. They also do not stick together.
However, the molybdenum sulfide wires feature another troublesome property that prevents a rapid succession to standard silicon transistors: They are rather unstable with temperature, the institute has found. "For this reason, we have relinquished to file a patent", an institute spokesperson said.
However, the research for the aspect of contacting will be continued.
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