Engineered Band Gap Pushes Graphene Closer to Displacing Silicon
A new method for engineering a band gap into graphene maintains its attractive electronic properties Graphene might bethe best conductor of electrons we know. However, as a pure conductor it can’t stop the flow of electrons like a semiconductor such as siliconcan. Silicon’s ability to create an on/off state for the flow of electrons makes it possible to create the “0” and “1” of binary digital logic for computing.
While many believe this has pretty much taken graphene out of the running for digital logic applications that depend on turning the flow of electrons on and off, it hasn’t stopped researchers from looking to see if there’s a way to engineer a band gap into it that will make graphene behave like a semiconductor. The pressure of Moore’s Law on silicon is too much not to look for a solution from every corner. The problem with these engineered band gaps is that they come at the cost of compromising the electronic properties of graphene that were so attractive in the first place—most notably its high conductivity.
Now a team of researchers at Columbia University has developed a graphene-based material that has a signifcant band gap without coming at the cost of sacrificing its attractive electronic properties. In research described in the journal Nature,the Columbia researchers have created what’s known as a van der Waal (vdW) heterostructure—a combination of different two-dimensional (2D) materials held together by atomic scale forces known van der Waal forces. The researchers have provided a new level of understanding about why band gaps emerge in these vdW heterostructures, and how to modify the stacking between the 2D layers to open a much larger band gap, potentially even without pressure.