In a landmark advancement that could redefine quantum sensing and information technologies, researchers have unveiled a novel method for detecting magnetic resonance utilizing nitrogen-vacancy (NV) centers in diamond with an innovative all-carbon Schottky contact configuration. This cutting-edge approach, demonstrated in research led by Le, Mayer, Magaletti, and their collaborators, offers a transformative route for integrating diamond-based quantum sensors with scalable electronic readouts, heralding a new chapter for quantum device engineering.
The nitrogen-vacancy center, a defect structure in diamond comprising a nitrogen atom adjacent to a lattice vacancy, has long been celebrated for its exceptional quantum coherence and sensitivity to magnetic fields under ambient conditions. These NV centers serve as atomic-scale sensors capable of detecting minute magnetic perturbations with unparalleled precision. Yet, one challenge has consistently hampered their broader adoption: the efficient and practical electrical detection of their resonance signals. Traditional optical detection schemes, although effective, demand bulky and costly setups, limiting the integration potential in compact quantum technologies.
Addressing this limitation, the team engineered an all-carbon Schottky contact directly on diamond, leveraging the remarkable material compatibility and electronic properties of carbon allotropes. The Schottky contact acts as a rectifying junction, enabling field-effect detection mechanisms that translate spin-dependent changes in the NV centers’ charge or spin states into measurable electrical signals. By circumventing the need for external optical components, this innovation paves the way for miniaturized, on-chip quantum sensors that can be more easily fabricated and integrated into complex electronics.
Central to this work is the precision fabrication of the all-carbon Schottky interface, which exploits graphene or related carbon materials placed in intimate contact with diamond. The researchers meticulously optimized the interface to ensure a high-quality barrier with minimal charge traps or defects, which could otherwise degrade the sensitivity. This fine-tuned interface is critical, as the Schottky barrier height directly influences the device’s responsiveness to the spin dynamics in the embedded NV centers.
Utilizing this novel platform, the team demonstrated the direct detection of magnetic resonance signals through field-effect measurements. Unlike conventional optically detected magnetic resonance (ODMR), which monitors changes in photoluminescence intensity, this field-effect detection approach observes changes in current flow or voltage across the Schottky contact induced by spin transitions of the NV centers. This paradigm shift not only simplifies the detection scheme but also enhances the compatibility with standard electronic measurement techniques prevalent in semiconductor technology.
Moreover, the researchers validated their device’s performance by conducting experiments at room temperature, underscoring the practicality and robustness of the sensing platform in real-world conditions. The NV centers retained their coherent spin properties, enabling precise magnetic field measurements without cryogenic cooling—an essential requirement for scalable sensor deployment. This robustness is crucial for applications spanning from biological imaging to navigation and fundamental physics experiments.
The implications of this technology extend into several burgeoning fields. In quantum computing, for example, NV centers are eyed as qubits, units of quantum information that demand sensitive initialization and readout. This electrical detection pathway could simplify qubit measurement, potentially accelerating the development of diamond-based quantum processors. Additionally, in nanoscale magnetometry, the ability to electrically read out NV-based sensors offers a compact and integrated solution for magnetic field detection in materials science and condensed matter physics.
Importantly, the all-carbon approach practically eliminates the mismatch issues that arise from interfacing diamond with traditional metal contacts, which often suffer from thermomechanical strain and interface degradation over time. Carbon-based contacts provide superior structural compatibility and electronic affinity, which ensures greater device stability and longevity critical for both research and commercial applications.
The researchers also highlighted the scalability prospects of their design. By employing lithographically defined carbon contacts, it is conceivable to fabricate arrays of NV sensors with high spatial resolution and multiplexed readout capabilities. This flexibility is key to realizing advanced quantum sensor networks and imaging modalities capable of probing complex magnetic phenomena across multiple spatial dimensions simultaneously.
In exploring the device physics, the team unraveled how the spin-dependent charge state transitions of the NV centers modulate the Schottky barrier height and, consequently, influence current flow. This detailed understanding bridges the quantum spin dynamics with classical semiconductor transport, enabling predictive device modeling and optimization. Such conceptual clarity is invaluable for tailoring sensor characteristics to specific applications, whether for enhanced sensitivity, speed, or robustness.
Furthermore, the researchers tackled challenges related to noise and sensitivity limits inherent in electronic detection schemes. Through meticulous engineering of the contact interfaces and electrical circuitry, they achieved a signal-to-noise ratio competitive with traditional optical methods. This parity suggests that future iterations could not only match but potentially surpass ODMR performance, especially when integrated with advanced low-noise electronics.
Another significant aspect of this work is the potential environmental and cost benefits. By eliminating the need for expensive, bulky lenses, lasers, and photon detectors that optical setups require, diamond quantum sensors based on field-effect detection can become more accessible and consumer-friendly. This democratization of quantum sensing technology opens pathways to sensors embedded in portable devices, wearable health monitors, and autonomous navigation systems.
Beyond sensing, the principles demonstrated here could inspire broader applications in spintronics and carbon-based electronics, where coherent spin manipulation and control in robust solid-state platforms remain hot topics. The fusion of diamond’s extraordinary quantum attributes with graphene’s and related materials’ electronic versatility stands at the frontier of next-generation quantum and electronic hybrid devices.
Looking ahead, the authors propose further research into optimizing the interface chemistry, enhancing NV center concentrations, and exploring alternative carbon allotropes for the contact material. Such avenues promise improvements in device performance metrics, including sensitivity, operational bandwidth, and thermal stability. Combining field-effect detection with other quantum control techniques could unlock unprecedented functionalities and foster a rich ecosystem of diamond-based quantum technologies.
In summary, this groundbreaking demonstration of field-effect detected magnetic resonance of NV centers in diamond using an all-carbon Schottky contact is poised to catalyze a paradigm shift in quantum sensing. By harmonizing the exceptional quantum properties of diamond with scalable electrical detection schemes, this innovation bridges fundamental quantum science and practical engineering, fueling new possibilities in computing, sensing, and information technologies. The elegant simplicity and scalability of this approach may well accelerate the advent of a new era in quantum-enabled devices, firmly anchoring diamond at the heart of future technological revolutions.
Subject of Research: Magnetic resonance detection of nitrogen-vacancy centers in diamond via field-effect using all-carbon Schottky contacts.
Article Title: Field-effect detected magnetic resonance of nitrogen-vacancy centers in diamond based on all-carbon Schottky contacts.
Article References:
Le, X.P., Mayer, L., Magaletti, S. et al. Field-effect detected magnetic resonance of nitrogen-vacancy centers in diamond based on all-carbon Schottky contacts. Commun Eng 4, 209 (2025). https://doi.org/10.1038/s44172-025-00541-z
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