Engineering of cooling mechanisms is a bottleneck in nanoelectronics. Whereas thermal exchanges in diffusive graphene are mostly driven by defect assisted acoustic phonon scattering, the case of high-mobility graphene on hexagonal Boron Nitride (hBN) is radically different with a prominent contribution of remote phonons from the substrate. A bi-layer graphene on hBN transistor with local gate is driven in a regime where almost perfect current saturation is achieved by compensation of the decrease of the carrier density and Zener-Klein tunneling (ZKT) at high bias. Using noise thermometry, we show that this Zener-Klein tunneling triggers a new cooling pathway due to the emission of hyperbolic phonon polaritons (HPP) in hBN by out-of-equilibrium electron-hole pairs beyond the super-Planckian regime. The combination of ZKT-transport and HPP-cooling promotes graphene on BN transistors as a valuable nanotechnology for power devices and RF electronics.
@article{arxiv.1702.02829,
title = {A graphene Zener-Klein transistor cooled by a hyperbolic substrate},
author = {W. Yang and S. Berthou and X. Lu and Q. Wilmart and A. Denis and M. Rosticher and T. Taniguchi and K. Watanabe and G. Feve and J. M. Berroir and G. Zhang and C. Voisin and E. Baudin and B. Plaçais},
journal= {arXiv preprint arXiv:1702.02829},
year = {2018}
}