Hot carriers in epitaxial graphene sheets with and without hydrogen intercalation: role of substrate coupling

Abstract

The development of graphene electronic devices produced by industry relies on efficient control of heat transfer from the graphene sheet to its environment. In nanoscale devices, heat is one of the major obstacles to the operation of such devices at high frequencies. Here we have studied the transport of hot carriers in epitaxial graphene sheets on 6H-SiC (0001) substrates with and without hydrogen intercalation by driving the device into the non-equilibrium regime. Interestingly, we have demonstrated that the energy relaxation time of the device without hydrogen intercalation is two orders of magnitude shorter than that with hydrogen intercalation, suggesting application of epitaxial graphene in high-frequency devices which require outstanding heat exchange with an outside cooling source.

Approaching Truly Freestanding Graphene: The Structure of Hydrogen-Intercalated Graphene on6H−SiC(0001)

“…Indeed the calculations show that in comparison to EMLG, QFMLG is a very flat graphene layer with a very homogeneous electronic density at the interface. This significant difference translates into a dramatic improvement of transistors after hydrogen intercalation [46,47]. It suggests that the adsorption distance is a valid parameter to assess the ideality of graphene.…”

Hot Carriers in CVD-Grown Graphene Device with a Top h-BN Layer

“…In general graphene systems, ≈ 3 suggests the supercollision cooling mechanism in disordered systems [13,18,33] and ≈ 4 suggests the two-dimensional acoustic phonon cooling processes in clean systems [34,35]. Particularly, ≈ 2, the heat diffusion described by the Wiedemann-Franz law, was found in graphene on bottom h-BN substrate systems, where bottom h-BN substrate acts as a thermal conduction layer, effectively reducing the electron-phonon coupling [14][15][16].…”