Exciton-exciton annihilation in hBN

Alexandre Plaud (1, 2) , Léonard Schué (1, 2) , Kenji Watanabe (3) , Takashi Taniguchi (3) , Frederic Fossard (4) , F. Ducastelle (4) , Annick Loiseau (1) , Julien Barjon (2)

1 LEM - ONERA - CNRS - Laboratoire d'étude des microstructures [Châtillon]
2 GEMAC - Groupe d'Etude de la Matière Condensée
3 NIMS - National Institute for Materials Science
4 LEM, UMR 104 CNRS-ONERA, Université Paris Saclay (COmUE) [Châtillon]

Known as a prominent recombination path at high excitation densities, exciton-exciton annihilation (EEA) is evidenced in bulk hexagonal boron nitride (hBN) by cathodoluminescence at low temperature. Thanks to a careful tune of the the exciton density by varying either the current or the focus of the incident electron beam, we could estimate an EEA rate of 2$\times$10$^{-6}$ cm$^{3}$.s$^{-1}$ at $T=10$ K, the highest reported so far for a bulk semiconductor. Expected to be even stronger in nanotubes or atomic layers, EEA probablly contributes to the luminescence quenching observed in low-dimensionality BN materials.

Mots clés: Ultraviolet light; Luminescence; Semiconductors; Excitons; Many body problems; Auger effect

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Alexandre Plaud, Léonard Schué, Kenji Watanabe, Takashi Taniguchi, Frederic Fossard, et al.. Exciton-exciton annihilation in hBN. Applied Physics Letters, 2019, 114 (23), ⟨10.1063/1.5090218⟩. ⟨hal-02131333v1⟩