Energy Relaxation of Hot Dirac Carriers in CVD Graphene-based Heterostructures*

The two dimensional character of graphene makes it a promising material to be used in the post-silicon electronics era. Despite the exceptional electronic properties, the lack of a bandgap in monolayer graphene limits its potential applications. The creation of heterostructures based on graphene and other two-dimensional crystals can help overcome some limitations. We present a fabrication process and magnetotransport measurements to study the hot carrier dynamics in scalable bilayer CVD graphene and graphene-on-WSe₂ heterostructures. Energy relaxation of hot Dirac fermions in these systems is experimentally investigated by Shubnikov–de Haas oscillations and weak localization^[1]. Energy loss rates in graphene-based heterostructures have been found to follow the predicted Bloch–Grüneisen power-law behaviour. The electron-phonon relaxation time has also been observed to be carrier density dependent. Hot carrier dynamics in graphene has considerable importance in determining the performance of high frequency and high power electronics, high-speed sensors and quantum Hall metrology for accurate measurements^[2].

[1] J. Huang et al., J. Phys.: Condens. Matter 27, 164202 (2016)
[2] M. R. Connolly et al., Nat. Nano. 8, 417–420 (2013)