Aberdeen-based HexSeed Technology has closed more than £600,000 in early-stage funding led by climate-tech venture builder Carbon13, with the Net Zero Technology Centre and Italian firm Vento participating. The round also unlocks an Innovate UK Partnership Grant awarded provisionally earlier this year.
HexSeed was incorporated in late 2025, making this one of the faster institutional raises in the UK semiconductor materials space. The founding team is Mark Tandy as chief executive, an Oxford MBA, alongside chief technology officer Dr Leonardo Santoni, a UCL chemistry PhD, and chief operating officer Dr Michael Glerum, a Cambridge engineering PhD.
The company sits at an unusual intersection: it operates a carbon capture and utilisation model, converting captured CO₂ into industrial-grade synthetic diamond films, then sells those films into semiconductor thermal management.
The technical thesis is straightforward. Gallium nitride transistors convert power far more efficiently than the silicon devices they are replacing, but they run hot, and heat is the constraint on GaN reaching its potential. Diamond is the best-known thermal conductor, yet growing it conventionally requires temperatures high enough to destroy a finished device.
Working with University of Bristol professors Paul May and Martin Kuball, HexSeed is developing a low-temperature microwave plasma process that grows diamond directly onto fabricated GaN devices without damaging them, pulling heat away from the active regions.
The market pull is the AI build-out. The International Energy Agency expects data centre electricity consumption to reach 945 TWh by 2030, and a large share of that power is lost as heat in power conversion.
"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."
On the cap table, Carbon13 leads — a venture builder rather than a conventional fund, which typically means an equity position taken at formation alongside programme support. The Net Zero Technology Centre, the Aberdeen-based body established through the Aberdeen City Region Deal, and Vento add strategic and international coverage. No valuation and no equity split were disclosed.
The Innovate UK Partnership Grant is the more capital-efficient half of the story. Grant funding is non-dilutive, so the equity cheque buys a smaller share of the company than £600,000 alone would suggest.
Proceeds will validate the coating process on commercial GaN devices and open pilot customer trials, with data centre power conversion hardware the initial target market. The next question for the cap table is whether pilot results arrive before the company needs to price a seed round.
Original source: UKTN — https://www.uktech.news/semiconductor/scotlands-hexseed-secures-investment-to-cool-ai-data-centre-chips-20260821
