Crystal quality of two-dimensional gallium was first obtained

Crystal quality of two-dimensional gallium was first obtained

For the first time ever gallium crystal just several atoms thick was obtained. Researchers say it may revolutionize manufacturing of ultra-thin electronics.

A team of researchers from the USA and India have obtained samples of gallium crystals as thick as 4-6 atoms – gallenene. It is believed that at some future date gallium may be used for the manufacturing of ultra-thin electronic devices.

In the early 2000s, two British researchers of Russian descent, Andre Geim and Konstantin Novoselov, managed to get graphene samples. Similarly to graphite, graphene consists of carbon atoms. The difference is that they are arranged in one layer. A matter in this form is called two-dimensional crystal and, as is the case with graphene, its properties may be much different from this similar matter in the usual crystalline form.

For example, it is known that graphite is used in pencils – is leaves visible trace on usual paper. However, graphene, despite being rather thin, is very durable. Moreover, it has a number of other unique properties, thanks to which it is now being used or strongly recommended to be used in a wide range of fields: electronics, energetics, defense industry, etc. The Nobel Prize in Physics 2010 was awarded jointly to Andre Geim and Konstantin Novoselov for the study of graphene properties.

It turned out that some other matters may also exist in the form of two-dimensional crystals. This has been proven only theoretically for some of such matters (after all, it was assumed for a long time that graphene cannot exist even in theoretical terms), some of them were obtained in the labs. As an example, two-dimensional crystal of tin is called stanene, silicon atoms of which silicon is formed are arranged in one layer and make up silicene.

Four researchers from the USA and India have tried to obtain two-dimensional crystal of gallium.  In the case of graphene, its first samples were obtained by using rather primitive technology. Usual adhesive tape was applied to peel off thin films. This was done over and over again until the fragments of monatomic film – graphene – were obtained. However, this technique is not suitable when treating gallium, since its atomic layers are linked much more stronger than those of graphite. Deposition of atoms from the gaseous phase, which is also often used to obtain two-dimensional crystals, is not suitable here too.

Therefore, researchers acted as follows. Molten gallium (its melting point is about 30°C/86°F only) was cooled until its crystallization began. Atomic layers have weak linkage and more colder laying was then applied to “tear off” several layers of atoms. Thus, a two-dimensional crystal was formed on the surface of laying, for which silicon or some other metals were used. The area of resulting gallium crystals has reached hundreds of square micrometers.

It is believed that gallium may be used in nanoelectronics, Moreover, the method used for its obtainment may be applied to get other two-dimensional crystals with a relatively low melting point.