Graphene‘s incredible strength, conductivity and flexibility have made it the “it” material of the science world right now. But it is not the only two dimensional material out there. Researchers have experimented combining graphene with other two dimensional materials to overcome one of its intrinsic problems: It can’t be turned “on” and “off” like semiconductors such as silicon. That means it has no control over the flow of electricity, ruling it out in its basic form for use in transistors. Many of the other two dimensional materials have promising applications on their own, which researchers are just now beginning to explore. Here are three super-thin materials that could soon compete with graphene (pictured above) for interest.
- Molybdenum disulfide: When stacked, MDS looks and feels like graphite — one of the 3D forms of graphene. But it is very different from graphene at the two-dimensional level. While graphene is a flat layer of carbon atoms, MDS is composed of molybdenum atoms sandwiched between two sulfur atoms. And unlike graphene, in its natural form it can serve as a semiconductor in transistors, making it appealing for use in electronics and solar cells. Scientists have been experimenting with combining the two materials to allow graphene to have transistor-friendly properties, but are now looking at using MDS on its own. It has properties similar to silicon, but requires the use of much less material and consume less energy.
- Silicene: When silicon is reduced to an atom thick layer, it takes on a slightly squished looking honeycomb structure similar to graphene. Like molybdenum disulfide, it can be used as a transistor in its natural form. It also shares one of graphene’s especially interesting properties: electrons move through it as if they were massless at a very fast pace. This means it conducts electricity faster than any commercially available semiconductor. Because silicon is so ubiquitous in current electronics, silicene could be much easier to adopt than other two dimensional materials. It was only synthesized for the first time last year though, so the research will take some time to mature. It also could turn out to be more difficult to make than graphene.
- Germanane: The element germanium is already used as a semiconductor, and actually formed the very first transistors in the 1940s. When reduced to a single layer of atoms, it forms a material known as germanane. Germanane conducts electrons five times faster than germanium and 10 times faster than silicon, which makes it ideal for creating faster computer chips. It is more stable than silicon and a better absorber and emitter of light. Manufacturers may also be able to produce it on existing equipment in large quantities, which would give it an advantage over emerging graphene manufacturing techniques.
Considering how recently these three materials have captured the attention of scientists, there could be many more two dimensional materials on the way. The next decade will tell whether any wins the title of “the next silicon.”