New Advances Achieved in Thermal Management Research For Diamond-Based Heterointerfaces

 

With the rapid development of electric vehicles, data centers, and new energy systems, high-power electronic devices are continuously evolving toward ever-higher power densities. Concurrently, the internal heat flux density within these devices continues to climb-with localized hotspots occasionally reaching intensities of 1200–4500 W/cm²-causing "heat dissipation capability" to gradually transition from a mere auxiliary metric into a critical factor that determines both device performance and reliability. Against this backdrop, traditional silicon-based materials-constrained by their inherent thermal conductivity and high-temperature tolerance limitations-are increasingly unable to meet the demands of this new generation of high-power devices, thereby compelling the industry to accelerate its transition toward novel material systems characterized by superior thermal conductivity.

 

Among the myriad candidate materials, diamond and carbon nanotubes (CNTs) have garnered significant attention due to their exceptionally high thermal conductivity. Diamond boasts a thermal conductivity exceeding 2000 W/m·K, while carbon nanotubes surpass even this figure, exceeding 3000 W/m·K; furthermore, the structural and chemical compatibility shared by these two materials endows them with immense potential for constructing highly efficient thermal interfaces.

However, in practical applications-even when the constituent materials themselves possess excellent intrinsic thermal properties-the interface situated between dissimilar materials invariably introduces significant thermal resistance, thereby emerging as a critical bottleneck that constrains overall heat dissipation efficiency. Consequently, the question of how to optimize thermal transport properties specifically at the interfacial level has emerged as a pivotal research frontier within the contemporary field of thermal management.

Recently, the research team led by Li Chengming at the University of Science and Technology Beijing published a research paper titled "Investigation of interfacial thermal resistance in diamond/CNT heterostructures via non-equilibrium molecular dynamics" in the *International Journal of Heat and Mass Transfer*. This study systematically analyzed-at the atomic scale-the various factors influencing interfacial thermal resistance as well as the underlying mechanisms for its modulation within diamond/CNT heterostructures.

 

The research findings reveal that the interfacial structure exerts a profound influence on thermal resistance. Specifically, the introduction of a titanium (Ti) coating layer resulted in a drastic reduction in interfacial thermal resistance, lowering it from approximately 41.6 m²·K/GW to a mere 7.89 m²·K/GW. This observed shift demonstrates that interposing a transitional layer between the CNTs and the diamond substrate can effectively enhance interfacial contact and augment the channels available for phonon coupling, thereby achieving a significant improvement in thermal conduction efficiency. Further analysis reveals that among various crystal plane orientations, the (100) plane consistently exhibits the lowest interfacial thermal resistance, indicating that crystal orientation exerts a significant influence on interfacial atomic arrangement and interactions.

 

Regarding surface modulation, the study demonstrates that most surface modifications are capable of enhancing interfacial thermal transport properties, with fluorine (F) modification yielding the most pronounced effects. Under optimal conditions, the interfacial thermal resistance can be reduced to approximately 4.45 m²·K/GW-a significant reduction compared to the unmodified interface. Concurrently, the impact of surface coverage on thermal resistance exhibits a nonlinear characteristic: as coverage increases, the interfacial thermal resistance generally decreases, reaching a minimum value at a coverage of approximately 75%; however, further increasing the coverage beyond this point may actually diminish the optimization effect. This result suggests that, in practical fabrication processes, it is unnecessary to pursue complete surface coverage; rather, an optimal structural regime exists.

 

Overall, this study systematically elucidates the governing principles for modulating interfacial thermal resistance in diamond/CNT systems. It clarifies the synergistic effects of the "crystal plane orientation-surface modification-coverage" triad on interfacial thermal transport and provides a unified explanation grounded in phonon-level physics. The findings demonstrate that by selecting the (100) crystal plane, introducing F modification, and optimizing the coverage, interfacial thermal resistance can be effectively reduced, thereby offering a clear pathway for the thermal management design of high-power electronic devices.

 

At the application level, this work provides a crucial theoretical foundation for the design of diamond/CNT composite thermal management materials and offers valuable insights for the thermal optimization of novel devices such as CNTFETs and GaN-on-diamond structures. Furthermore, the systematic analysis based on molecular dynamics simulations helps to minimize trial-and-error costs during experimental procedures and enhances the efficiency of interfacial engineering design.

 

Looking ahead, the paper notes that further experimental validation of the proposed interfacial modulation strategies remains necessary. Additionally, efforts must be directed toward advancing the fabrication techniques for large-area diamond materials and improving crystal orientation control technologies. Moreover, the development of controllable and stable processes for interfacial modification-as well as the successful integration of these structural designs into actual electronic devices-remain critical directions for future research.