New energy-efficient memory could replace flash drives

The team from Edinburgh University, along with two Korean institutes, built a device that records data using a mechanical, carbon nanotube arm that moves up and down to create or break a current.

While flash drives themselves represent improvement on traditional hard disk drives (HDDs) in terms of speed, noise, power consumption and reliability, they still have to draw power when writing. This becomes more noticeable in small devices when a user has high-resolution screens and various applications competing for power.

Essentially, the goal for memory research is to find a way of switching transistors on and off at the nanoscale with greater speed and lower energy consumption.

Previous attempts to use carbon nanotube transistors for memory storage have hit a stumbling block because they had low operational speed and short memory retention times.

Looking for a simpler approach, the team realised it could use the carbon nanotubes mechanically, as project lead Prof Eleanor Campbell of Edinburgh explained.

‘What happens with flash memory, to gate the transistor [store data] you have electrons tunnelling through an oxide layer and that takes time — on the order of microseconds.

‘So with our idea, instead of using a tunnelling mechanism, we have a little mechanical arm that we can move down to charge and to make contact with the gate — the speed is only limited by the mechanical resonance of the arm, so on the scale of tens of nanoseconds.’

The team has demonstrated a prototype that managed 500 repeated programming and erasing cycles, although it believes it can improve on this.

‘We have demonstrated that the idea works and the next step is for the engineers, if they want to take this further and find an industrially useful way of making these,’ Campbell said.

Through the two Korean collaborators, Konkuk University and Seoul National University, the recent work has come to the attention of Samsung.