Band Gap Renormalization, Carrier Multiplication, and Stark Broadening in Photoexcited Black Phosphorus

Zhesheng Chen (1) , Jingwei Dong , Evangelos Papalazarou (2) , Marino Marsi (2) , Christine Giorgetti (3) , Zailan Zhang (4) , Bingbing Tian (5) , Jean-Pascal Rueff (6, 7) , Amina Taleb-Ibrahimi , Luca Perfetti (3)

1 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
2 LPS - Laboratoire de Physique des Solides
3 LSI - Laboratoire des Solides Irradiés - Irradiated Solids Laboratory
4 College of Information Engineering, Shenzhen University
5 CNRS - Centre National de la Recherche Scientifique
6 LCPMR - Laboratoire de Chimie Physique - Matière et Rayonnement
7 SSOLEIL - Synchrotron SOLEIL

We investigate black phosphorus by time- and angle-resolved photoelectron spectroscopy. The electrons excited by 1.57 eV photons relax down to a conduction band minimum within 1 ps. Despite the low band gap value, no relevant amount of carrier multiplication could be detected at an excitation density 3–6 × 1019 cm–3. In the thermalized state, the band gap renormalization is negligible up to a photoexcitation density that fills the conduction band by 150 meV. Astonishingly, a Stark broadening of the valence band takes place at an early delay time. We argue that electrons and holes with a high excess energy lead to inhomogeneous screening of near surface fields. As a consequence, the chemical potential is no longer pinned in a narrow impurity band.

Domaines: Matière Condensée [cond-mat]; Autre [cond-mat.other]

Zhesheng Chen, Jingwei Dong, Evangelos Papalazarou, Marino Marsi, Christine Giorgetti, et al.. Band Gap Renormalization, Carrier Multiplication, and Stark Broadening in Photoexcited Black Phosphorus. Nano Letters, 2018, 19 (1), pp.488-493. ⟨10.1021/acs.nanolett.8b04344⟩. ⟨hal-02264121⟩