Physics / mechanism
Diamond is a metastable allotrope of carbon with sp³ tetrahedral bonding. Key properties: bandgap 5.47 eV (ultrawide), breakdown field ~10 MV/cm, thermal conductivity 2200 W/m·K (highest of any bulk material), carrier mobility electrons ~4500 cm²/V·s / holes ~3800 cm²/V·s. Boron-doped p-type diamond is achievable; n-type remains difficult. CVD synthesis (MPCVD) now produces single-crystal wafers up to 2” with defect densities approaching 10³ cm⁻², though 4” remains pre-commercial. NV-centre coherence times reach milliseconds at room temperature. Diamond Schottky diodes already demo >1 kV blocking with mΩ·cm² on-resistance. State-of-play: material quality is investor-grade but wafer economics are not yet.
Competitive landscape
Competing ultrawide-bandgap (UWBG) materials: AlN (6.2 eV bandgap, mature epitaxy, weaker thermal conductivity ~320 W/m·K), Ga₂O₃ (4.8 eV, scalable melt-grown substrates, but poor thermal management), cBN (similar gap to diamond, near-zero commercial traction). SiC and GaN are incumbent power semiconductors but are wide- not ultrawide-bandgap and top out below diamond’s theoretical Baliga figure of merit.
| Material | Bandgap (eV) | Thermal cond. (W/m·K) | Wafer maturity |
|---|---|---|---|
| Diamond | 5.47 | 2200 | 2”, nascent |
| Ga₂O₃ | 4.8 | 20 | 4–6”, advancing |
| AlN | 6.2 | 320 | 2–4”, limited |
Where the value is (opportunity-led, all routes)
Diamond value-chain cluster
Diamond shows up at several points of the electronics stack, all sitting on a common substrate base. Same material, different role: worth holding as one cluster because a move at the base (single-crystal substrate cost/size, sovereign supply) or in demand (AI thermal, defence RF, quantum) ripples across the others.
Base layer: substrate & material growth (feeds every application above)
Application layers (the three value vectors, ranked by opportunity size)
Equipment and deposition tooling sits underneath all of these (CVD reactors: sp3 Diamond, Seki Diamond Systems), a picks-and-shovels layer that benefits if any device layer scales.
Other diamond markets & applications
Beyond the electronic and quantum stack above, diamond serves several established markets. Most are lower VC-relevance for us directly, but they matter to the thesis because they drive CVD diamond volume and cost, which is the base-layer gate for the RF, thermal and quantum plays: cheaper, larger single-crystal wafers arrive on the back of these markets’ scale.
| Market | Use of diamond | Companies (KB) | Relevance |
|---|---|---|---|
| Optics & photonics | Optical windows for high-power lasers and gyrotrons; IR / X-ray / synchrotron optics; Raman lasers; diamond photonics | Element Six (optical grade), Coherent / II-VI, Edmund Optics, Tydex, Diatope | Adjacent; defence / laser pull overlaps RF |
| Electrochemistry & water | Boron-doped diamond (BDD) electrodes: water / wastewater treatment, ozone generation, electrochemical sensors | Condias, Element Six (electrochemical grade) | Niche specialty industrial |
| Industrial / superhard | Cutting tools, abrasives, wear and optical coatings (diamond’s original and largest market, commoditised) | Sumitomo, Beijing Worldia, Zhongnan, Applied Diamond, Sandvik | Low VC-relevance; scales material supply |
| Lab-grown gemstone / consumer | Jewellery-grade CVD / HPHT stones | Diamond Foundry (VRAI / Aether), WD Lab Grown, IIa Technologies, New Diamond Era | The cash engine that funds and scales CVD reactor capacity |
| Biomedical / diagnostics | Fluorescent and drug-delivery nanodiamonds; NV biosensing (overlaps quantum sensing) | Orbis Diagnostics, QDTI | Niche; quantum-sensing crossover |
The strategic point: the gem and industrial markets are the volume base that pulls down CVD single-crystal cost and pushes up wafer size. That base-layer trajectory is the decisive watch for whether the RF/power and quantum-device layers become economic this decade (see Frontier below).
Verification note (17 Jun 2026): pages marked unverified are auto-mapped (
data_source: sonnet-*,verified: false); their descriptions and funding figures need a primary-source check before being cited in any memo or external artefact. Qnami in particular was auto-described as cat-qubit cavity tooling, which is wrong (it is NV scanning-probe magnetometry), corrected here.