Electron-Phonon Interaction in Graphene/Polar Substrate Interface

This work focuses on the study of two processes; Auger and Diffusion of an electron-surface optical phonon (ESOP) in monolayer graphene on polar substrates such as silicon dioxide silicon carbide hafnium oxide or hexagonal boron nitride. We showed that; charge carrier relaxation channels are affected when deposing graphene on polar substrates. Thus the fundamental physical mechanisms controlling the ultra-fast dynamics in graphene are influenced by the choice of polar substrate temperature charge carrier density and the thickness of the graphene/polar substrate interface. The significant role of collinear and ultrafast scattering enabling Auger processes including charge multiplication is a key to improving photovoltaic production and high sensitivity photo-detectors. In addition we have shown that surface phonons of polar substrates produce an electric field that interacts with the electrons of the monolayer graphene deposited above. Indeed the ESOP interaction causes a resonant coupling between the electron sublevels and the surface vibration modes inducing the increase of the Rabi splitting of the electrons energy levels in monolayer graphene on polar dielectrics.