Produced a good conductive alternative to graphene

Researchers have succeeded in producing borophene. Borophene is a ‘two-dimensional’ relative of graphene and consists of the element boron. The now famous graphene consists of carbon. Like graphene, borophene consists of a single layer of atoms in a honeycomb structure.

In January 2014 it came to light that it should theoretically be possible to produce a single-layer material from boron atoms, which has now actually been achieved. Boron in its normal state is a semi-metal or metalloid and functions as a semiconductor, but as a ‘two-dimensional’ film it has good conductive properties.

To produce borophene, the researchers set up a vacuum chamber under an ultra-high vacuum containing a silver substrate. Then the boron was vaporized with an electron beam and then deposited on the silver. The silver substrate was needed because silver does not react with boron. The material was vapour-deposited at temperatures between 450 and 700 degrees Celsius. This proved to work best at temperatures around 550°c.

The boron precipitated on the silver in two different ways. At a higher deposition rate and lower temperatures, the boron film became homogeneous or nearly flat. When the precipitation rate was lower and the temperature higher, a ribbed film or ‘striped-phase nanoribbons’ formed. It is not yet clear which of the two variants will be most useful.

There are, however, ideas about how the phases react. For example, there are theories that the properties of the corrugated film will be very different in different directions. Scientists suspect that borophene will have more metallic properties in the direction parallel to the ‘wrinkles’, while perpendicular to the ripples the material may be less or non-conductive. The material could then act as a unidirectional metal. The latter could be interesting, says one of the researchers Andrew Mannix on the Science news site.

Also, based on theoretical research, the researchers suspect that the tensile strength of borophene is higher than that of any other known material. We have not yet succeeded in separating the film from the silver and it is still necessary to consider how to protect the borophene from the environment. Outside the vacuum chamber, the borophene quickly undergoes various chemical reactions with the outside air. It may be possible to wrap the borophene in a protective layer of silicon or something else to make it stable.

The way to produce the material is quite simple, which means that labs all over the world should be able to replicate it without too much trouble. Scientists from various universities published their methods in the journal Science. Graphene was not made until 2004. This was followed by some other flat materials, such as stanene.

Graphene and similar materials have many potential applications for electronics, such as for roll-up screens, sensitive sensors and tiny chips. The materials are light and super strong, but large-scale production has proved an obstacle so far.

Borophene. Source: Science