In recent months, a new sense of excitement has spread through the graphene research community. These guys are no longer focused on what they can do with single layers of carbon chickenwire. Instead they have a more ambitious plan.
The new goal is to take single layers of high quality graphene and pile them on top of each other to create what physicists call van der Waals heterostructures, layer cakes of carbon crystals each just a single atom thick that promise to behave in entirely new ways. The hope is that this will open the way to undreamt of applications in superconductivity, semiconductor physics and so on.
But there is a problem. Creating layer cakes of crystalline sheets is fraught with difficulty, so research groups around the world are racing to find better ways of doing it.
Today Xu-Dong Chen and a few buddies at Nankai University in China say they have developed a new and easier way to do it that opens up the possibility of exploring the potential of these devices in much greater detail.
Ideally, physicists would simply grow one layer of graphene on top of another but nobody has worked out how to do this, particularly when they want to orient each layer’s crystal structure in different directions. What’s more, graphene grown in this way is of much lower quality than the stuff they can get by cleaving single layers from a bigger lumps.
This cleaving process creates flakes of high-quality graphene sheets but it also introduces other problems. Nobody has cracked the problem of how to carve these flakes into the required shapes and then to pick them up individually and place them in the required spot.
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