Diamond & Quantum Weekly | Oct 19–25, 2026

Reporting window: October 19, 00:00 to October 25, 23:59, 2026 (Beijing time)

This week: A catch-up on a 12-inch polycrystalline diamond membrane; a diamond–copper cold plate remains at the sample stage; an NV laser-threshold study is formally published.

1. Key Takeaways

The most significant materials development covered in this issue actually appeared the week before. A paper published online on October 15 by a Peking University-led team demonstrated a process linking MPCVD growth, laser edge treatment, automated release and silicon-substrate reuse for a 12-inch polycrystalline diamond membrane. We missed this important study in the previous issue, so it is added here under our correction policy with its actual publication date retained. Its significance is a shift in the question from whether a large-area film can be made to whether it can be manufactured repeatably at a calculable cost. The disclosed results do not yet establish stable production yield across batches.

The clearest commercial update this week came from Sleek’s diamond–copper cold plate. The company says it has completed sample development and basic performance tests; customer sampling, reliability testing and production-line construction remain future steps. In quantum sensing, an NV laser-threshold readout study was formally published on October 22, although its experiment had been public as a preprint since September 2025. Formal publication is worth noting, but it should not be recast as a first demonstration this week.

2. P1 Focus

[Important catch-up from the previous issue] A Peking University-led team demonstrates a manufacturing process for 12-inch polycrystalline diamond membranes.

• Original online date: October 15, 2026. Reason for catch-up: An important study was missed last week; the accepted manuscript has since been obtained and key process and characterization data checked.
• The National Science Review paper uses a 12-inch silicon wafer as the growth substrate, followed by MPCVD deposition, an approximately 20 μm annular edge cut and automated release. The paper reports a release time of about 10 seconds per membrane and says the substrate can be retained for reuse.
• Figure 1 and the main text report through-plane thermal conductivity of about 1,700 W/(m·K) at a film thickness of approximately 30 μm. Raman measurements across 16 regions show a mean peak position near 1333 cm⁻¹ and mean full width at half maximum of about 5.9 cm⁻¹. These data come from the authors’ accepted manuscript; they are not measurements in a customer cooling system.
• The work follows a 2024 Nature report on releasing a 2-inch polycrystalline membrane. The paper does not disclose the batch count, denominator for full-area yield, number of substrate-reuse cycles, or system-level TBR and reliability data needed to assess production readiness.

Sources: NSR paper, online October 15 | 2024 Nature precursor study.

3. CVD / MPCVD and Thermal Management

Sleek diamond–copper cold plate: from sample development to in-house testing. Project updates on October 20 and public information on October 21 indicate that the team has produced cold-plate samples and conducted basic in-house performance tests. The reported processes include pressure infiltration, sintering and diffusion bonding. Customer sampling, reliability tests and production-line construction are planned next. Comparable system thermal resistance, interface resistance, CTE, lifetime and customer-qualification data have not been disclosed; this is not yet volume delivery. Source: Economic Information Daily.

CETC’s cubic-AlN/diamond heterostructure FET: announced this week, but the paper was not first published this week. The group announced the development on October 21; the corresponding Advanced Functional Materials paper had already appeared online on September 18. The route uses MOCVD to grow cubic AlN on diamond, form a two-dimensional hole gas and demonstrate an enhancement-mode FET. The paper abstract reports room-temperature mobility of 314 cm²/(V·s). This is active-device research, not an order for thermal-management substrates. CETC announcement | Paper.

4. Quantum Devices and Sensing

Nature Communications formally published Schall and co-authors’ NV-center laser-threshold magnetometry study on October 22. The matching preprint first appeared on September 5, 2025 and was revised in May 2026. The experiment used a 1042 nm dual-dielectric laser cavity to achieve 100% optical contrast and reported output up to about 50 mW. The <400 fT/√Hz and best 127 fT/√Hz figures are photon-shot-noise sensitivity limits calculated from ODMR curves, not measured magnetic-field sensitivity. The “up to 590-fold” comparison concerns the combined trade-off between intrinsic dynamic range and a theoretical sensitivity limit; it does not mean a 590-fold improvement in measured sensitivity. Published paper | arXiv version history.

5. Conferences and Exhibitions

Post-event information from the Guilin conference. The 18th China Symposium on Diamond-Related Materials and Applications and the International Diamond Innovation and Applications Conference were held on October 14–16. Post-event reports appeared on October 20 and 23. Topics included high-quality MPCVD, diamond/copper and CVD thermal transport, precision laser processing, heterostructures and functional applications. The reports mainly provide talk titles and summaries. We have not found independently verifiable new process data, customer qualifications or orders, so the conference itself is not counted again as a new event this week. Post-event report 1 | Post-event report 2.

6. Social-Media Watch

Social media continued to circulate leads on Wiwynn’s OCP diamond microchannel concept, Sifangda’s test orders and a Japanese diamond MOSFET circuit. These refer respectively to technical material presented on October 14, business status disclosed earlier, and a company notice dated October 13. They merit follow-up, but repost dates do not make them new developments. Quantum-computing performance claims without primary experimental evidence or independent corroboration are not included.

7. What to Watch Next

For the 12-inch membrane, watch cross-batch full-area yield, reuse cycles, the temperature used for thermal-conductivity measurement and TBR after attachment. For cold plates, track customer sampling and reliability. For the enhancement-mode diamond FET, follow RF performance and lifetime. Materials related to the Xinjiang Kunpeng heat-sink project award and whether the DMA Zhengzhou conference has formally changed dates remain open pending primary documents from the organizer or purchasing entity.

8. Full-Edition Preview

The full edition breaks down the 12-inch membrane process and the boundaries of Figure 1 data, compares the NV paper’s 2025 preprint with its 2026 journal version, and evaluates thermal-management commercialization across four stages: samples, company testing, customer qualification and orders.

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Sources

• National Science Review, October 15, 2026: 12-inch polycrystalline diamond membrane process
• Nature, 2024: 2-inch polycrystalline diamond membrane precursor study
• Economic Information Daily, October 21, 2026: Sleek diamond–copper cold-plate update
• China Electronics Technology Group, October 21, 2026: AlN/diamond heterostructure announcement
• Advanced Functional Materials, September 18, 2026: Cubic AlN/diamond heterostructure FET
• Nature Communications, October 22, 2026: NV laser-threshold magnetometry paper
• arXiv, September 5, 2025: Preprint and version history
• Electronic Engineering Times China, October 20 and 23, 2026: Guilin conference post-event report 1 | report 2