A technique developed by a research team from the University of Delft is said to be capable of producing fast, low power and flexible polycrystalline silicon transistors at low cost. Tests showed the thin film transistors created using the process exhibited mobilities as high as those of conventional polysilicon conductors.
The team says the ability to print silicon ink onto substrates has existed for some time, but the process has required a 350°C thermal annealing step – too hot for many of the flexible surfaces that developers might want to use. The method is said to bypass this step by treating liquid silicon ink with a single laser pulse.
"It was very simple," said Professor Ryoichi Ishihara, who led the Delft research team, with collaborators at the Japan Advanced Institute of Science and Technology. "We coated liquid polysilane directly on paper by doctor blading in an oxygen free environment. Then we annealed the layer with an excimer laser. And it worked," he said.
The most immediate application of the method is said to be in wearable electronics. However, Prof Ishihara believes the team's work, which involves improving the production process to include additional non silicon layers, will enable further applications.
"The process can be expanded to biomedical sensor and solar cells," Prof Ishihara added, "and will also realise stretchable – even edible – electronics!"
pic: R Ishihara, M Trifunovic, TUDelft. A high-mobility polysilicon layer was directly formed on paper by coating liquid silicon, which was annealed by pulsed laser-light.
Author
Graham Pitcher
Source: www.newelectronics.co.uk