EXTREMELY high resolution and low energy thin, flexible displays could be on the way, with a new way of creating pixels just a few hundred nanometres across.
Scientists with the Oxford University's Department of Materials found they could sandwich a seven nanometre thick layer of a phase change material (Germanium-Antimony-Tellurium, or GST) between two layers of a indium tin oxide electrode materials, then use a tiny current to 'draw' images within the sandwich 'stack'.
The team then went on to demonstrate that the stacks of phase change materials could be turned into pixel-like devices. These nano-pixels which measure 300 by 300 nanometres in size can be electrically switched 'on and off' at will. Put millions of these nano-pixels together, and it would be possible to create extremely high-resolution displays.
According to Professor Harish Bhaskaran, the team were exploring the relationship between the electrical and optical properties of phase change materials when the idea to create the stack came up.
The stack is created by using a sputtering technique where a target is bombarded with high energy particles so that atoms from the target are deposited onto another material as a thin film.
"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," he said. "We also discovered that altering the size of the bottom electrode layer enabled us to change the colour of the image."
The Oxford team is continuing to explore the new innovation, but has patented the discovery.
"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," said Professor Bhaskaran.
"This makes them potentially useful for 'smart' glasses, foldable screens, windshield displays, and even synthetic retinas that mimic the abilities of photoreceptor cells in the human eye."