HexSeed Technology raises over £600,000 to help keep the hyperscale data centre boom from overheating

HexSeed Technology has raised over £600k in early funding, led by Carbon13, with participation from Net Zero Technology Centre and Vento Ventures. The cumulative investment unlocks a Partnership Grant from Innovate UK, awarded on a provisional basis earlier this year.

Gallium nitride transistors convert power far more efficiently than the silicon devices they’re replacing, but they run hot, and heat is the main barrier standing between GaN and its full potential. Diamond is the best thermal conductor known, but growing it the conventional way requires temperatures that would destroy a finished semiconductor device.

The company was founded in late 2025 by Mark Tandy (CEO, Oxford MBA), Dr Leonardo Santoni (CTO, PhD in chemistry from UCL) and Dr Michael Glerum (COO, PhD in Engineering from Cambridge). Together with researchers from the University of Bristol HexSeed is developing a low-temperature microwave plasma process that grows diamond coatings directly onto finished GaN devices, pulling heat away from the active regions so they run harder, last longer, and use less energy.

The funding will be used to demonstrate the coating process on commercial GaN power devices and progress toward pilot customer engagements, with data centre power conversion hardware as the initial target market.

“Data centres are on track to consume a significant share of UK grid capacity within the decade, and a large proportion of that energy is lost as heat in power conversion. This funding will allow us to take our low-temperature diamond coating technology which we are developing from laboratory demonstration to working GaN devices,” said Mark Tandy.