Researchers at the Korean IBS, in collaboration with Sungkyunkwan University, have designed a novel graphene-based stretchable and flexible memory device for wearable electronics.
The team has constructed a memory called two-terminal tunnelling random access memory (TRAM), where two electrodes, referred to as drain and source, resemble the two communicating neurons of the synapse in the brain. While mainstream mobile electronics use the so-called three-terminal flash memory, the advantage of two-terminal memories like TRAM is that two-terminal memories do not need a thick and rigid oxide layer. While Flash memory is more reliable and has better performance, TRAM is more flexible and can be scalable, according to the team.
IBS scientists carefully selected the thickness of the insulating h-BN layer as they found that a thickness of 7.5 nanometers allows the electrons to tunnel from the drain electrode to the graphene layer without leakages and without losing flexibility.
Flexibility and stretchability are the two key features of TRAM. When TRAM was fabricated on flexible plastic (PET) and stretachable silicone materials (PDMS), it could be strained up to 0.5% and 20%, respectively. In the future, TRAM can be useful to save data from flexible or wearable smartphones, eye cameras, smart surgical gloves, and body-attachable biomedical devices.
Also important is the fact that TRAM has better performance than other types of two-terminal memories known as phase-change random-access memory (PRAM) and resistive random-access memory (RRAM).