Ultra-low-power digital memory for portable devices

The technology could give future portable devices much longer battery life between charges.

‘I think anyone who is dealing with a lot of chargers and plugging things in every night can relate to wanting a cell phone or laptop whose batteries can last for weeks or months,’ said electrical and computer engineering professor Eric Pop.

Flash memory used in mobile devices stores bits as charge, which requires high programming voltages and is relatively slow. Industry has been exploring faster but higher power phase-change materials (PCMs) as an alternative. In PCM memory, a bit is stored in the resistance of the material, which is switchable.

Pop’s group lowered the power per bit to 100 times less than existing PCM memory by focusing on size; rather than the metal wires standard in industry, the group used carbon nanotubes.

‘The energy consumption is essentially scaled with the volume of the memory bit,’ said graduate student Feng Xiong. ‘By using nanoscale contacts, we are able to achieve much smaller power consumption.’