Unraveling the bandgap nature in hexagonal boron nitride Auteur(s): Cassabois G.
Conférence invité: IW2DC (Campofelice di Roccella, IT, 2016-05-30) Ref HAL: hal-01358450_v1 Exporter : BibTex | endNote Résumé: I will discuss our recent experiments by two-photon spectroscopy demonstrating that hBN is an indirect bandgap material. I will show that the optical properties of hBN are profoundly determined by phonon-assisted transitions involving either virtual or real excitonic states. I will present our measurements of the exciton binding energy by two-photon excitation, leading to the estimation of 6.08 eV for the single-particle bandgap in hBN. I will also show that transverse optical phonons at the K point of the Brillouin zone assist intervalley scattering, which becomes observable because stacking faults in bulk hexagonal boron nitride provide a density of final electronic states. |