As recently as 2010, human-made silicene – an atom-thin form of silicon – was purely theoretical. But now the exotic material has been used to make transistors, and researchers have found that silicene's electrical properties lend it extraordinary potential in powering the next generation of computer chips.
The silicene transistors performed in line with the theory, which has computer engineer Deji Akinwande and his team at the University of Texas at Austin suggesting that silicene could soon be taken up as a production material by the semiconductor industry. Such a development would make computer chips dramatically faster, smaller, and more efficient because silicene's structure allows electrons to traverse the circuit without encountering as many objects (thereby making their journey faster). But the big achievement here, Akinwande says, "is the efficient low-temperature manufacturing and fabrication of silicene devices for the first time."
Silicene has developed a reputation in its short life as a material that is notoriously difficult to work with. Much like that other wonder material, graphene, which is made from carbon, silicene's thickness of just a single layer of silicon atoms gives it its extraordinary properties. But it also makes it difficult to produce and, unlike graphene, it's unstable when exposed to air.
The researchers developed a method for fabricating the silicene that sandwiches it between a thin layer of silver and a nanometer-thick layer of alumina (aluminum oxide, naturally found in certain rocks and precious gems). With the protective layers in place, they could transfer it safely to a silicon dioxide wafer with the silver side up. Some of the silver was then gently scraped off to leave two electrical contacts and a strip of silicene between them – a transistor.
This technique may not work in commercial practice, but it's nonetheless a crucial first step. Akinwande will now look to find new methods for making silicene, as no doubt will others in the field.
A paper describing the research was published in the journal Nature Nanotechnology.
Source: University of Texas at Austin
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