Researchers develop flexible memory devices based on hybrid of graphene oxide and titanium oxide

University of Exeter nanotech researchers claim technology could be used in 'smart' clothing

Engineers at the University of Exeter claim to have developed a new material for flexible and transparent memory devices based on a hybrid of graphene oxide and titanium oxide.

They claim that the devices will not only be eco-friendly to produce, but also low cost. They envisage them not just being embedded in mobile phones, computers and televisions, but also even in clothing.

The research is published in the scientific journal ACS Nano, although it was first revealed in December last year.

At the time, Professor David Wright, an Electronic Engineering specialist from the University said: "The conventional way of producing devices using graphene can be time-consuming, intricate and expensive and involves many process steps including graphene growth, film transfer, lithographic patterning and metal contact deposition.

"Our new approach is much simpler and has the very real potential to open up the use of cheap-to-produce graphene devices for a host of important applications from gas and bio-medical sensors to touch-screen displays."

He added: "Using graphene oxide to produce memory devices has been reported before, but they were typically very large, slow, and aimed at the 'cheap and cheerful' end of the electronics goods market.

"Our hybrid graphene oxide-titanium memory is, in contrast, just 50 nanometres long and eight nanometres thick, and can be written to and read from in less than five nanoseconds - with one nanometre being one-billionth of a metre and one-nanosecond a billionth of a second."

Professor Craciun, a co-author of the work, added: "Our work offers the opportunity to completely transform graphene-oxide memory technology, and the potential and possibilities it offers."

Current flash storage devices are based on silicon because they offer high storage density combined with relatively low fabrication costs, Wright and Craciun write in their research paper. However, flash memories rely upon charge storage for their operation, suffer from a slow programming speed, poor endurance and relatively high operating voltages.

In addition, their continuous miniaturization (to increase the storage density) is expected soon to reach its fundamental scaling limit due to the difficulty in retaining charge (electrons) in shrinking dimensions.

While the concept of graphene oxide resistive memories is not new, the issue of how small they can be made and how fast they might be able to operate, when properly developed, has received less research.

The researchers claim that the hybrid of graphene oxide and titanium oxide could potentially be produced at processes of as little as eight nanometres, with responsiveness of sub-five-nanosecond speeds.