A material that surpasses certain physical limits of silicon has been used to fabricate a prototype microchip in Switzerland.
École polytechnique fédérale de Lausanne’s (EPFL’s) Laboratory of Nanoscale Electronics and Structures (LANES) made the chip with molybdenite, which is claimed to improve upon silicon in terms of miniaturisation, electricity consumption and mechanical flexibility.
‘We have built an initial prototype, putting from two to six serial transistors in place, and shown that basic binary logic operations are possible, which proves that we can make a larger chip,’ said LANES director Andras Kis.
According to a statement, the laboratory unveiled the potential of molybdenum disulfide (MoS2) — a relatively abundant, naturally occurring mineral — in early 2011.
Its structure and semiconducting properties are said to make it an ideal material for use in transistors, so it can therefore compete with silicon, the most highly used component in electronics.
‘The main advantage of MoS2 is that it allows us to reduce the size of transistors and thus to further miniaturise them,’ said Kis.
It has not been possible until now to make layers of silicon less than two nanometres thick, because of the risk of initiating a chemical reaction that would oxidise the surface and compromise its electronic properties.
Molybdenite, however, can be worked in layers only three atoms thick, making it possible to build chips that are at least three times smaller. At this scale, the material is still very stable and conduction is easy to control.
Molybdenite is comparable with silicon in terms of its ability to amplify electronic signals, with an output signal that is four times stronger than the incoming signal.
Kis said that this proves the considerable potential for creating more complex chips.
‘With graphene, for example, this amplitude is about one,’ said Kis. ‘Below this threshold, the output voltage would not be sufficient to feed a second, similar chip.’