HexSeed Raises £600k to Develop Diamond Cooling Technology for AI Data Centres

HexSeed Technology, a carbon capture and utilisation company converting captured carbon dioxide into engineered materials, has raised more than £600,000 (approximately €700,000) in early-stage funding. The round was led by Carbon13 with participation from the Net Zero Technology Centre and Vento Ventures. The company said the combined investment unlocks a partnership grant from Innovate UK awarded on a provisional basis earlier this year.

The company was founded in late 2025 by Mark Tandy, chief executive, Dr Leonardo Santoni, chief technology officer, and Dr Michael Glerum, chief operating officer, and works with the University of Bristol.

What the funding will support

HexSeed is developing a low-temperature microwave plasma process intended to grow diamond coatings directly onto completed gallium nitride (GaN) power devices. Diamond is the best-known thermal conductor, but conventional growth requires temperatures that would destroy a finished semiconductor. The company is working with University of Bristol professors Paul May, a specialist in diamond materials, and Martin Kuball, who works on semiconductor devices and thermal management.

The technology remains under development. HexSeed said the capital will fund demonstration of the coating process on commercial GaN power devices and progress towards pilot customer engagements, with data-centre power conversion hardware as the initial target market. Tandy said the funding takes the process from laboratory demonstration to working GaN devices.

The commercial argument rests on power conversion losses. GaN transistors convert power more efficiently than the silicon devices they are replacing but run hotter, and the company argues heat is the principal constraint on their performance. HexSeed cites International Energy Agency projections that data-centre electricity consumption will reach 945 TWh by 2030 as AI-optimised facilities are built out.

Why it matters for private capital

Power availability, not chip supply, is increasingly the binding constraint on data-centre construction, and that has widened investor interest from compute itself to the electrical and thermal layer beneath it. HexSeed sits at the earliest end of that opportunity: a pre-revenue materials science company whose route to market runs through semiconductor manufacturers rather than data-centre operators. For allocators, it illustrates the long duration and technical risk characteristic of deep-tech commercialisation, and the role grant co-funding plays in bridging it.