In a landmark breakthrough that could reshape the future of semiconductor technology, researchers have achieved remarkably high hole mobilities in gallium nitride (GaN), a wide-bandgap semiconductor material predominantly known for its role in solid-state lighting and high-performance radio frequency electronics. This advance promises to unlock new pathways for exploring p-type doping phenomena, quantum oscillations, and ultimately could pioneer cryogenic GaN complementary metal–oxide–semiconductor (CMOS) devices. The key to this achievement lies in the establishment of a polarization-induced two-dimensional hole gas (2DHG) at the interface between GaN and aluminum nitride (AlN).
Historically, the utilization of GaN in electronic devices has been significantly hindered by the challenges associated with p-type doping. Unlike electron conduction, which is relatively well-understood and efficiently harnessed in GaN, hole conduction suffers from inefficient doping techniques and inherently low hole mobility. This low mobility restricts the ability to probe quantum transport phenomena and map the valence band structure via techniques such as Shubnikov–de Haas oscillations. The recent success in observing these quantum oscillations in p-type GaN signals a major leap forward, as this had remained elusive until now.
The scientific team engineered a heterostructure wherein the intrinsic electric polarization of the GaN/AlN interface induces a highly confined two-dimensional hole gas. This gas exists within two distinct valence bands of GaN: the light-hole (LH) band and the heavy-hole (HH) band. Both bands are populated degenerately by holes, which, remarkably, exhibit substantially different mobilities. Light holes reach mobilities as high as 2,000 cm² V⁻¹ s⁻¹, while the heavy holes achieve mobilities of approximately 400 cm² V⁻¹ s⁻¹ at cryogenic temperatures around 2 K.
These mobility values represent a significant improvement over previously reported hole mobilities in GaN and provide an unprecedented experimental platform to investigate hole dynamics. By exploiting the distinct quantum oscillations tied to each valence band, the research team successfully extracted precise values for the sheet densities, quantum scattering times, and the effective masses of both light and heavy holes. This level of insight is crucial to furthering our understanding of valence band engineering, an essential aspect for the adaptation of GaN in next-generation electronics.
Shubnikov–de Haas oscillations—oscillations of electrical resistance in a material under strong magnetic fields—serve as a powerful probe of the electronic structure. The observation of these oscillations in a two-dimensional hole gas of GaN underscores the high quality of the heterostructure as well as the high mobility and coherence of holes in this system. The clear resolution of oscillations from both the light-hole and heavy-hole pockets provides a compelling validation that GaN’s valence band landscape can now be experimentally accessed with exceptional clarity.
This breakthrough holds significant implications for the development of cryogenic electronics, particularly in the context of quantum computing control systems. With its wide bandgap, excellent thermal stability, and now enhanced hole conduction, GaN-based devices could operate efficiently at ultra-low temperatures, offering lower power dissipation and increased operational speed—unlike traditional silicon-based devices. These attributes are highly desirable for the scalability and robustness of quantum computing platforms.
The GaN/AlN heterostructure showcases the powerful role of intrinsic polarization effects in semiconductor systems. Instead of relying on traditional impurity doping—which often hampers mobility due to ionized impurity scattering—the utilization of polarization-induced charges enables the formation of a two-dimensional hole gas with exceptionally low disorder. This paradigm shift could herald novel device architectures where polarization engineering becomes a central tool for tailoring electronic properties.
Furthermore, the ability to isolate and manipulate two distinct hole subbands in GaN presents fascinating opportunities to explore spin-orbit interactions and many-body effects that are fundamental to spintronics and topological quantum materials. The degenerate occupation of both light-hole and heavy-hole bands implies that device engineers may harness band mixing effects and anisotropic transport behavior, which have been theorized but not experimentally accessible until now.
One of the most exciting aspects of this advancement is the compatibility of GaN with existing semiconductor fabrication processes, offering a pathway to integrate high-mobility hole channels with state-of-the-art electronics. This integration could prove invaluable for complementary logic circuits where both electrons and holes are employed, overcoming significant hurdles that have historically limited GaN-based CMOS logic to electron conduction only.
From a materials science perspective, the research provides critical insights into the subtle interplay between epitaxial strain, polarization charge, and valence band structure in nitride semiconductors. Control of these parameters will enable fine-tuning of transport characteristics and quantum phenomena in future engineered heterostructures, expanding the design space for tailored electronic and optoelectronic properties.
Moreover, the quantum scattering times extracted from the oscillation data highlight the intrinsic quality of the hole gas and the nature of scattering mechanisms at play. Longer quantum scattering times correlate to reduced disorder and enhanced coherence of electronic states, which are essential for quantum device applications requiring high-fidelity operation and long coherence times.
This discovery also revitalizes fundamental interest in hole transport physics in wide-bandgap materials. While electron transport in GaN has been studied extensively, holes have remained a challenging frontier, limiting theoretical understanding and potential practical applications. The newfound ability to experimentally probe hole subbands and their quantum transport parameters marks a significant milestone in semiconductor physics.
Looking ahead, the implications stretch beyond quantum computing; high-mobility p-type GaN layers could also revolutionize power electronics by enhancing device efficiency and switching speeds while reducing heat generation. Given GaN’s exceptional robustness in harsh environments, combining high hole mobility with existing electron mobility frameworks could create highly efficient, reliable power transistors and integrated circuits.
In summary, the breakthrough reported by Chang and collaborators provides a compelling proof-of-concept that polarization engineering at GaN/AlN interfaces can produce high-mobility hole gases capable of supporting quantum oscillations. This opens entirely new avenues for the study and application of hole physics in GaN, with transformative consequences anticipated for cryogenic electronics, quantum technology, and advanced semiconductor devices. As researchers continue to explore these heterostructures, the full potential of high-mobility holes in GaN appears poised to fuel a new era of innovation in electronics and quantum materials science.
Subject of Research: High-mobility holes in gallium nitride semiconductors and quantum oscillation phenomena in two-dimensional hole gases.
Article Title: High-mobility holes in gallium nitride and their quantum oscillations.
Article References:
Chang, C.F.C., Dill, J.E., Zhang, Z. et al. High-mobility holes in gallium nitride and their quantum oscillations. Nat Electron (2026). https://doi.org/10.1038/s41928-026-01590-8
DOI: https://doi.org/10.1038/s41928-026-01590-8
