Banchory-based HexSeed Technology has raised more than £600,000 in early-stage funding to scale a low-temperature process that coats gallium nitride power chips with ultra-thin diamond films — targeting the fast-growing thermal bottleneck inside AI data centres.
The round was led by Cambridge-based climate-tech venture builder Carbon13, with participation from Aberdeen’s Net Zero Technology Centre and Italian venture firm Vento Ventures. The cumulative investment unlocks a Partnership Grant from Innovate UK, awarded on a provisional basis earlier this year.
Founded in late 2025, HexSeed is developing a low-carbon microwave plasma process that grows diamond coatings directly onto finished GaN devices at temperatures low enough not to destroy them — something conventional diamond growth cannot do. The coating pulls heat away from the active regions of the chip, letting the device run harder, last longer, and use less energy.
The work is being carried out in collaboration with researchers at the University of Bristol, including Professor Paul May, an expert in diamond materials, and Professor Martin Kuball, a specialist in semiconductor devices and thermal management (University of Bristol).
Why GaN — and why heat is the bottleneck
Gallium nitride transistors convert power far more efficiently than the silicon devices they are replacing, and are increasingly the technology of choice for the high-density power conversion hardware used inside hyperscale data centres. But they run hot, and heat is the main barrier standing between GaN and its full potential.
Diamond is the best thermal conductor known to materials science. The catch is that growing it conventionally requires temperatures that would destroy a finished semiconductor. HexSeed’s process is designed to avoid that trade-off, applying the coating after the device is complete.
The company’s investors have framed the opportunity in similar terms. Carbon13 described HexSeed’s approach as unlocking “a crucial bottleneck in the $91B data centre industry”, noting that AI-driven demand is pushing the sector from silicon to GaN, which creates a new thermal problem for coatings like HexSeed’s to solve.
A live market — 945 TWh and rising
The market pull is significant. The International Energy Agency’s Base Case now projects global data centre electricity consumption to more than double to around 945 TWh by 2030, slightly more than Japan’s current total electricity consumption, with AI-optimised facilities the dominant driver. A large share of that power is lost as heat in power conversion — the exact stage of the stack HexSeed is targeting.
“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 HexSeed chief executive Mark 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.”
The team and next steps
HexSeed was founded in late 2025 by three co-founders: Tandy (CEO, Oxford MBA); Dr Leonardo Santoni (CTO, PhD in chemistry from UCL); and Dr Michael Glerum (COO, PhD in Engineering from Cambridge).
The new capital 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 (UKTN, Compound Semiconductor).
For Scotland’s technology cluster, HexSeed sits at an increasingly crowded and increasingly strategic junction: an Aberdeenshire deep-tech startup, backed by the region’s Net Zero Technology Centre, working on the physical bottleneck inside the same AI infrastructure boom that this month drew £300 million of debt financing to DataVita’s Lanarkshire data-centre expansion. If the diamond-on-GaN process holds up outside the lab, the company’s addressable market is measured not in Scottish terms but in terawatt-hours.
