news digest ♦ Novel Devices
comprise IBM scientists and engineers from Albany and Yorktown, New York; Almaden, California; and Europe.
“Scaling to 7nm and below is a terrific challenge, calling for deep physics competencies in processing nano materials affinities and characteristics. IBM is one of a very few companies who has repeatedly demonstrated this level of science and engineering expertise,” said Richard Doherty, technology research director, The Envisioneering Group.
Beyond 7 nanometers, the challenges dramatically increase, requiring a new kind of material to power systems of the future, and new computing platforms to solve problems that are unsolvable or difficult to solve today, says the company.
British researchers create building blocks for new high-resolution display technology
Phase-change film ‘sandwich’ shows potential for thin, flexible nano-pixel displays
A team led by scientists at Oxford University has shown the possibility of combining optical and electrical control in ultrathin phase-change films to create pixels just a few hundred nanometers across. They think their research, published in this week’s Nature, could pave the way for extremely high-resolution and low-energy thin, flexible displays for applications such as ‘smart’ glasses, synthetic retinas, and foldable screens.
Phase-change materials (materials that can change from an amorphous to a crystalline state) such as the alloy germanium antimony tellurium (GST) have for years been used in optical storage media such as rewritable DVDs. More recently, such materials have been investigated as candidates for the next generation of electrically operated non-volatile memories. In this latest study, the researchers found that by sandwiching a seven nanometer thick layer of GST between two layers of a transparent electrode made from indium tin oxide (ITO) they could use a tiny current to ‘draw’ images within the sandwich ‘stack’. The layers of the GST sandwich are created using a sputtering technique where
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a target is bombarded with high-energy particles so that atoms from the target are deposited onto another material as a thin film.
Initially still images were created using an atomic force microscope but the team went on to demonstrate that such tiny ‘stacks’ can be turned into prototype pixel-like devices. These ‘nano- pixels’ - just 300 by 300 nanometres in size - can be electrically switched ‘on and off’ at will, creating the coloured dots that would form the building blocks of an extremely high-resolution display technology.
Whilst the work is still in its early stages, the Oxford team has filed a patent on the discovery with the help of Isis Innovation, Oxford University’s technology commercialisation company. Isis is now discussing the displays with companies who are interested in assessing the technology, and with investors.
“We didn’t set out to invent a new kind of display,” said Harish Bhaskaran of Oxford University’s Department of Materials, who led the research. “We were exploring the relationship between the electrical and optical properties of phase change materials and then had the idea of creating this GST ‘sandwich. We found that not only were we able to create images in the stack but, to our surprise, thinner layers of GST actually gave us better contrast. We also discovered that altering the size of the bottom electrode layer enabled us to change the colour of the image.’
He added: “Because the layers that make up our devices can be deposited as thin films they can be incorporated into very thin flexible materials - we have already demonstrated that the technique works on flexible Mylar sheets around 200 nanometres thick.”
Peiman Hosseini of Oxford University’s Department of Materials, first author of the paper, said: “One of the advantages of our design is that, unlike most
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