Scientists have pushed graphene’s performance to record levels, boosting its speed and purity with a clever trick called “proximity screening”, reducing electronic noise at the atomic scale.
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In a study published in Nature, researchers demonstrated a major improvement in the electronic quality of graphene by using proximity screening, a method that enhances charge uniformity and boosts carrier mobility.
The results not only improve the reliability of graphene-based devices but also strengthen its prospects for use in advanced electronics, sensors, and quantum technologies.
Why Graphene Still Needs Help
Graphene has remarkable electrical and mechanical properties and has driven huge technological growth. But in practice, devices have struggled to match its theoretical promise. Issues like charge inhomogeneity, scattering from impurities, and defects can degrade performance and reduce mobility, which are key for any high-speed or quantum device.
To address this, the researchers turned to a combination of graphene with hexagonal boron nitride (hBN), a 2D material known for its insulating and dielectric qualities. Their goal was to create a cleaner environment for electrons to move freely and consistently. No defects, no noise.
How the Devices Were Built
The team created double-gated Hall bar structures by sandwiching monolayer graphene between two hBN layers. The top layer served as a dielectric gate, with a graphite flake as the bottom gate. To enable proximity screening, the bottom hBN layer was made ultrathin, just 3-4 atomic layers. This setup allowed image-charge effects to smooth out potential fluctuations greater than 10 nanometres across the graphene sheet.
The entire device was assembled using van der Waals stacking techniques, with precision lithography to define its geometry. This meticulous construction helped maintain clean interfaces and limit disorder, which is essential to achieve high electronic quality.
Testing at Ultra-Low Temperatures and Fields
To assess the material’s performance, researchers tested electrical measurements under a range of temperatures and magnetic fields. Hall effect measurements were used to map how electrons moved through the device under different gate voltages, revealing mobility and charge distribution.
The data showed major improvements: mobility reached as high as 5.7×107 cm2/Vs at low temperatures and carrier densities around 1.5×1011 cm-2. This massive, fivefold increase over previous graphene records puts the material on par with long-standing 2D performance leaders like GaAlAs heterostructures.
Evidence of Quantum Precision
The study also tracked quantum mobility, which is an indicator of how cleanly electrons travel in the presence of a magnetic field. The proximity-screened devices showed quantum mobilities around 107 cm2/Vs, supporting clear observations of Landau quantization and the quantum Hall effect at fields as low as one millitesla.
Such sensitivity also enabled the detection of Shubnikov-de Haas oscillations at these ultra-low fields, indicating extremely narrow Landau levels and exceptional electronic quality. Importantly, charge fluctuations near the Dirac point were reduced to less than 10 K, serving as further proof of the system’s uniformity.
Although some complex quantum states, like fractional quantum Hall phases, were suppressed under this setup, the researchers found that short-range interactions were still possible. This suggests the devices still have room for exploring novel quantum behaviours.
What This Means for Nanotechnology
The results have major implications for future devices. Higher electron mobility and reduced disorder mean graphene can finally start delivering on its promise for ultra-fast transistors, quantum sensors, and flexible electronics.
The approach could also be extended to other 2D materials and heterostructures, allowing scientists to build cleaner, more controllable devices with new electronic properties. Importantly, the study has shown that proximity screening is compatible with existing fabrication techniques, making it feasible for scale-up and integration into complex nanosystems.
The next steps will involve scaling up the fabrication process and testing proximity screening with a broader range of 2D materials. The researchers also emphasise the need to further explore how charge transport is influenced by device edges and interactions with other layers in heterostructures.
In the long term, this work lays the foundation for building high-performance, disorder-free electronic systems.
Journal Reference
Domaretskiy, D., et al. (2025). Proximity screening greatly enhances electronic quality of graphene. Nature 644, (646-651). DOI: 10.1038/s41586-025-09386-0, https://www.nature.com/articles/s41586-025-09386-0
