Superfast carbon memory

Graphene could make computer hard drives denser and speedier.

Published in Technological Review.com

Graphene, a flat sheet of hexagonally arranged carbon atoms, can transport electron very quickly:-

1. This made it a promising material for high radio frequency logic circuits, 
   
2. Transparent electrodes for flexible flate panel displays,
3. High surface area electrodes for ultracapacitors.

Now researchers at the National University of Singapore have made computer memory devices using graphene. Researchers  have made hundreds of prototype graphene memory devices and they work reliably, according to Barbaras Ozyilmaz.

• The key to making memory elements is a material that can have two different states. That is because computer memory is stored as two bits: 1 and 0.
• Hard drives  also need to be nonvolatile, which means the material should be able to hold on to those states without  requiring power.
• Today's hard disks are made of magnetic cobalt alloys and they store bits as one of two magnetic orientations of a small area on the disk.
• Ozyilmaz and his colleagues came up with an easy way to make graphene hold its two different levels of conductivity or resistance. Switching between these levels requires applying and removing an electric field.Researchers deposit a thin layer of a ferroelectric material on top of the graphene. 
• Ferroelectrics have an intrinsic electric field and applying a voltage changes the direction of the field and helps graphene sustain its conductivity.