A graphene Zener-Klein transistor cooled by a hyperbolic substrate

Area of Science:

• Nanoelectronics
• Materials Science
• Condensed Matter Physics

Background:

• Thermal management is critical in nanoelectronic device engineering.
• Graphene's thermal properties differ significantly when on hexagonal boron nitride (hBN) substrates compared to diffusive graphene.
• Remote phonon interactions from the hBN substrate play a key role in thermal transport in graphene/hBN systems.

Purpose of the Study:

• To investigate the thermal transport mechanisms in bilayer graphene on hBN transistors operating at high bias.
• To identify novel cooling pathways beyond traditional phonon scattering.
• To explore the potential of these mechanisms for advanced electronic applications.

Main Methods:

• Utilized noise thermometry to accurately measure device temperatures.
• Operated bilayer graphene on hBN transistors in a regime of current saturation.
• Analyzed the role of Zener-Klein tunneling (ZKT) and its interaction with substrate phonon modes.

Main Results:

• Observed that Zener-Klein tunneling (ZKT) in high-bias graphene/hBN transistors initiates a novel cooling mechanism.
• Demonstrated the emission of hyperbolic phonon polaritons in hBN by out-of-equilibrium electron-hole pairs.
• Showcased a cooling pathway that becomes significant beyond the super-Planckian regime.

Conclusions:

• The combination of ZKT transport and hyperbolic phonon polariton emission provides an effective cooling pathway in graphene/hBN heterostructures.
• This finding presents graphene on BN transistors as a promising nanotechnology for high-performance power devices and radio-frequency electronics.
• Understanding and engineering these cooling mechanisms are crucial for future nanoelectronic advancements.