Study paves way for mass production of flexible computers

Flexible electronic devices could become easier to manufacture thanks to a novel component developed at Surrey University, researchers claim.

Computers that can be rolled up like paper are often seen as the next generation of electronics but one of the difficulties in mass producing them is designing components that are robust enough to be identically replicated millions of times.

A team at Surrey’s Advanced Technology Institute (ATI), working with scientists from Phillips, have now demonstrated how a special type of thin-film transistor could reduce the complexity of flexible digital circuits, opening the possibility they could be mass produced more easily and at low cost.

‘People have talked about flexible electronics for 20 years now,’ lead researcher Dr Radu Sporea told The Engineer. ‘The reality is that it’s fine in lab but if you make even five devices they’re not going to be the same.’

The source-gated-transistors (SGTs), developed by Surrey University and Philips a decade ago, operate five to ten times more slowly than conventional transistors but Sporea claims they are more reliable, more energy efficient and better at withstanding electrical interference, meaning they don’t need additional circuitry to protect them.

This is because the SGTs, which are essentially switches, control the flow of current at the point of contact between the metal and the semiconductor material rather than in the semiconductor itself, meaning fewer electrons flow through it and reducing the chance that its properties will change over time.


‘You can imagine very low-cost technologies, that don’t have any screening, they may be printed on plastics or fabrics, and the electromagnetic fields from wifi or mobile phones might disturb these circuits,’ said Sporea. ‘The idea is that the SGT is better able to be resilient to this sort of thing.’

He added that SGTs could be used with any semiconductor material including silicon, organic materials, zinc oxide and potentially graphene, the one atom-thick form of carbon that has been heralded as the next major semiconductor.

Sporea’s team is now planning to build demonstration circuits to show how the SGTs can be used in flexible devices.

The team’s work on the use of SGT’s in digital circuits is published in the Nature journal Scientific Reports.