Combining two types of molecular boron nitride could create a hybrid material used in faster, more powerful electronics

Both types of boron nitride conduct heat and can provide electrical insulation, but one, h-BN, is soft, and the other, c-BN, is hard. So, we wanted to see if they could be used together to create materials with interesting properties.

For example, combining their different behaviors could make a coating material effective for high temperature structural applications. C-BN could provide strong adhesion to a surface, while h-BN’s lubricating properties could resist wear and tear. Both together would keep the material from overheating.

Making boron nitride

This class of materials doesn’t occur naturally, so scientists must make it in the lab. In general, high-quality c-BN has been difficult to synthesize, whereas h-BN is relatively easier to make as high-quality films, using what are called vapor phase deposition methods.

In vapor phase deposition, we heat up boron and nitrogen-containing materials until they evaporate. The evaporated molecules then get deposited onto a surface, cool down, bond together and form a thin film of BN.

Our research team has worked on combining h-BN and c-BN using similar processes to vapor phase deposition, but we can also mix powders of the two together. The idea is to build a material with the right mix of h-BN and c-BN for thermal, mechanical and electronic properties that we can fine-tune.

Our team has found the composite substance made from combining both forms of BN together has a variety of potential applications. When you point a laser beam at the substance, it flashes brightly. Researchers could use this property to create display screens and improve radiation therapies in the medical field.

We’ve also found we can tailor how heat-conductive the composite material is. This means engineers could use this BN composite in machines that manage heat. The next step is trying to manufacture large plates made of a h-BN and c-BN composite. If done precisely, we can tailor the mechanical, thermal and optical properties to specific applications.

In electronics, h-BN could act as a dielectric – or insulator – alongside graphene in certain, low-power electronics. As a dielectric, h-BN would help electronics operate efficiently and keep their charge.

C-BN could work alongside diamond to create ultrawide band gap materials that allow electronic devices to work at a much higher power. Diamond and c-BN both conduct heat well, and together they could help cool down these high-power devices, which generate lots of extra heat.

H-BN and c-BN separately could lead to electronics that perform exceptionally well in different contexts – together, they have a host of potential applications, as well.

Our BN composite could improve heat spreaders and insulators, and it could work in energy storage machines like supercapacitors, which are fast-charging energy storage devices, and rechargeable batteries.

We’ll continue studying BN’s properties, and how we can use it in lubricants, coatings and wear-resistant surfaces. Developing ways to scale up production will be key for exploring its applications, from materials science to electronics and even environmental science.

Pulickel Ajayan receives funding from the Army Research Laboratory and the Army Research Office.

Abhijit Biswas does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.