MONDAY, 2 NOVEMBER 2015Semiconductors form the bedrock of modern electronics. For example, almost every form of modern computerised device now relies on transistors made from semiconductor materials, whose unique electrical conductivity properties allow them to amplify, switch and convert electrical energy most efficiently. They perform so well, and have such a large array of options available when it comes to modifying that performance, that it is difficult to envision how we can improve upon them. However, Penn State materials scientists have found that the incorporation of vanadium dioxide can be used to augment and give us fine control over so-called field effect transistors. They knew that the electrons of vanadium dioxide in its metal state would flow freely, and in its insulator state, cannot flow. This binary transistive property is also the foundation of computing and information storage. The researchers reckoned that by adding this metal dioxide close to a transistor they could improve, and help control, its functionality.
However, the real challenge was that this dark blue solid had never been extracted in a sufficiently pure state as the ‘wafer’ thin film required for electronic devices. This month in Nature Communications, Engel-Herbert’s group at Penn State report a method to generate crystalline films with the appropriate vanadium to oxygen ratio, by forming a ‘library’ of different ratios, which can be used to quickly query for the optimal combination, as opposed to the tedium of trial and error. Published and ongoing research has already indicated that this methodology may open up the way for designing super high frequency switches, selectors that can crisply segment reading and writing to individual memory cells, and of course a new generation of field effect transistors, to name but a few possibilities. And yet despite this potential, ‘Vanadium Dioxide Valley’ just does not have quite the same ring to it.
Written by Alex Bates.