Semiconductor materials startup HexSeed Technology has raised more than £600,000 in early-stage funding to scale its low-temperature diamond coating technology designed to prevent AI power semiconductors from overheating.
The investment round was led by climate-tech venture builder Carbon13, alongside backing from the Net Zero Technology Centre and Italian venture capital firm Vento.
Founded in late 2025 by chief executive Mark Tandy, CTO Dr Leonardo Santoni, and COO Dr Michael Glerum, HexSeed develops advanced thermal management materials for semiconductors.
Gallium nitride transistors have long been seen as an ideal successor to silicon-based chips, due to their more efficient conversion of power. HexSeed intends to support this transition with its technology.
The company operates a carbon capture and utilisation model, turning captured CO₂ into industrial-grade synthetic diamond films.
In partnership with researchers at the University of Bristol, HexSeed is developing a low-temperature microwave plasma technique to grow diamond coatings directly onto fabricated GaN chips.
The coating dissipates heat away from active device regions, extending chip lifespans, improving thermal efficiency, and lowering energy consumption across hyperscale facilities.
The startup will use the funding to validate the coating process on commercial GaN devices and launch pilot customer trials, targeting data centre power conversion hardware as its primary 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,” said Tandy.
“This funding will allow us to take our low-temperature diamond coating technology which we are developing from laboratory demonstration to working GaN devices.”
