Doping Advanced Material with Light
The ability to selectively add charges to materials, a process called doping, has been instrumental in allowing our electronics to become more powerful. We are quickly approaching the limits how modern electronics though, so new systems will have to be devised, and new materials to build them with. Researchers at Berkeley Lab and the University of California, Berkeley have recently worked with one material that has some very interesting properties, including the ability to be doped using light, instead of complicated chemistry.
Graphene is an atom-thick sheet of carbon with amazing electron transport capabilities. It would make an ideal material for future electronics, except that it lacks a bandgap, which is necessary to stop currents. Boron nitride has a similar structure to graphene, but does possess a bandgap. The Berkeley researchers decided to work with a combination of the two materials called a bilayer graphene boron nitride (GBN) heterostructure. Other researchers have worked with this before, but used chemistry or electrostatic gating to control its electronic properties. This new work though demonstrated that light could be used to induce doping on the material, and with that the researchers were able to control the material's electronic properties.
While this new technique definitely offers a simpler and more scalable approach to doping a GBN heterostructure, we cannot expect it in our computers any time soon. Samples kept in a dark room eventually had their doping fade away. While this lack of stability may be a problem for us, for scientific studies and applications, it should prove very useful.
Source: Berkeley Lab