Graphene, for anyone who still doesn’t know, is a material made up of a one-atom thick sheet of hexagonally-linked carbon atoms. It is very electrically-conductive, inexpensive to produce, and is simultaneously the thinnest material in existence yet also one of the strongest.
To create the semiconductors, the Norwegian team starts by “bombing” a graphene substrate with gallium atoms, within a vacuum chamber. Those atoms stick to the graphene, and clump together with one another to form gallium droplets. On the underside of each droplet, where it meets the graphene, the gallium atoms naturally arrange themselves to match the hexagonal pattern of the graphene.
Next, arsenic molecules are also introduced to the graphene sheet, as the gallium atoms continue to rain down. Both arsenic molecules and gallium atoms are absorbed into the existing gallium droplets. Once inside a droplet, the arsenic travels to the bottom, where it combines with the gallium atoms. They form into a crystalline structure, on the bottom of the droplet.