Scientists Say Diamond Precision May Cut a Path to Scalable Quantum Devices

If successful, the method could unlock scalable, room-temperature quantum systems that function outside the constraints of cryogenic labs. The goal is to build compact, energy-efficient quantum accelerators for a number of uses and applications that stretch across fields and industries.

“The ability to widely distribute and integrate quantum accelerators with classical devices offers a potential pathway for long-term adoption in the technological ecosystem,” the researchers write in their study. :Such devices could be implemented in massively-parallelised quantum computing systems for high-performance computing applications, and in offline and autonomous systems, such as vehicles, satellites, in medical environments, and for edge computing applications.”

The Problem With Top-Down Approaches
At the heart of this fabrication challenge is the NV center: the above mentioned nitrogen atom adjacent to a vacancy in the diamond lattice. These defects can be used to represent and manipulate quantum information due to their unique optical and spin properties, and they operate reliably even at room temperature.

However, manufacturing NV centers at scale remains difficult. Traditional methods such as ion implantation lack precision and reproducibility. In this method, ions are shot into diamond to create vacancies and nitrogen substitutions, but this process introduces significant spatial uncertainty, inconsistent yields and unwanted magnetic noise from surrounding defects, the researchers suggest. The randomness of this “top-down” process makes it ill-suited for assembling the densely packed, precisely aligned arrays needed for quantum computing or high-fidelity sensing.


A Bottom-Up Blueprint
The new study proposes a multi-step “bottom-up” method for building NV centers atom by atom, adapted from processes already used to fabricate phosphorous-based qubits in silicon.

The researchers report that their process starts with a pristine, hydrogen-terminated diamond surface. A scanning tunneling microscope (STM) is used to remove individual hydrogen atoms from the surface with sub-nanometer precision. This creates reactive patches of carbon atoms, which are, essentially, chemical “hooks” where nitrogen-containing molecules can attach. After nitrogen is adsorbed onto these spots, the surface is overgrown using chemical vapor deposition (CVD), embedding the nitrogen atoms into the diamond lattice to form NV centers.

The approach is based on hydrogen depassivation lithography (HDL), which has been widely used on silicon and germanium substrates. The authors argue that with modifications, the method can be adapted for use on diamond.

This matters because scalable quantum systems require many identical qubits arranged in predictable geometries. For quantum computing, NV centers need to be spaced just 5–10 nanometers apart with placement accuracy better than ±1 nanometer to ensure reliable entanglement and gate operations via dipolar coupling, according to the study. For quantum sensing applications, such as magnetic field detection, broader spacing (over 30 nm) may be preferable to minimize unwanted interactions. In both cases, homogeneity in spacing — or, uniformity — and orientation is critical.

Atom-scale fabrication promises to meet these exacting demands, enabling large-scale production of uniform NV arrays. This could dramatically improve device performance and bring quantum sensing and computing out of the lab and into commercial applications.


Progress and Proof of Concept
While the method is not yet fully realized, early demonstrations are promising. Previous studies on silicon have shown deterministic single-atom placement using similar techniques. On diamond, preliminary STM-based lithography has successfully desorbed hydrogen atoms from the surface with some spatial control. In one case, Quantum Brilliance reproduced a surface manipulation technique originally developed by another team, suggesting reproducibility.

Furthermore, nitrogen retention during overgrowth has been experimentally demonstrated. In certain configurations, up to 34% of nitrogen adsorbates survived the CVD process and were incorporated into the diamond lattice. Aligning these findings with improved precursor design and adsorption chemistry could push this figure higher.


Open Questions and Future Research Directions
Even with promising early progress, the scientists report that future work will like focus on several unknowns for building quantum devices using diamonds.

One of the biggest hurdles is how to precisely place nitrogen atoms into the diamond lattice to form the NV center. STM lithography is well established in silicon but remains in its early stages for diamond, where single-atom precision has yet to be consistently demonstrated. This level of control is critical because even small missteps in spacing or alignment can throw off how the system behaves.

Another unknown is the best way to deliver nitrogen onto the diamond surface. Researchers are testing various nitrogen-containing molecules, but they are still trying to fine one that can check all the boxes: they must stick only to the target spot, survive the heat and chemical conditions during later steps and settle into the lattice in the right orientation to reliably form a functional NV center.

Even when nitrogen atoms are successfully added, not all of them end up forming working NV centers. Some stick, others don’t, and why this happens isn’t fully understood. Getting this stage right is important because a lot of effort goes into preparing the surface, and low conversion rates mean a lot of that effort goes to waste. Scientists are now exploring whether tuning the chemistry of the nitrogen molecule itself might help promote the right kind of defect to form, especially one that aligns with the crystal in a predictable way.

Scaling up the process adds another layer of difficulty. Placing a single NV center is one thing; placing thousands in a precise pattern is another. STM, the current tool of choice, is extremely accurate but slow. It works one point at a time. Some newer techniques, like extreme ultraviolet light, are still being tested but could help speed things up.

The diamond material itself also poses unique challenges. To avoid magnetic noise that could disrupt quantum behavior, the diamond must be nearly flawless, for example, free of stray atoms or defects. Yet, the tools needed to manipulate its surface, like STM, require the diamond to conduct electricity. That means adding dopants — foreign atoms that carry charge — but those same dopants can create noise. One workaround being studied is to keep the conductive parts far away from the delicate regions where NV centers are formed.

Finally, the chemistry at the surface has to be tightly controlled. If too many hydrogen atoms are stripped away, the exposed surface may react with itself and seal shut, making it impossible for nitrogen to attach. So researchers need to remove just the right number of hydrogen atoms in just the right places, and nothing more.


What’s Next
Ultimately, there’s work to be done, but if further experimentation proves out and the approach becomes feasible, the researchers write that this could shift the trajectory of diamond-based quantum technologies, enabling portable quantum accelerators that operate at room temperature without cryogenic infrastructure. Applications could include satellite-based quantum sensors, edge-computing modules, autonomous navigation systems and high-performance hybrid classical-quantum computers.

To get there, the researchers call for collaborative work across fields — surface chemistry, nanofabrication, quantum optics — to refine each step of the process. They stress that while technical hurdles remain, no known physical law prohibits the method’s success.

The team writes: “In this perspective article we have outlined a method for atomically-precise manufacturing of NV centres using HDL. The efficacy of similar techniques has already been demonstrated on silicon and germanium, and we believe that there are no fundamental reasons why these cannot be adapted to diamond.”