(T. Barisien, F. Bernardot, L. Legrand, M. Chamarro, C. Testelin, A. W. Chin)

Semiconducting nanocrystals synthetized in solution through chemical processes currently attract a wide attention for they can be produced at low cost and exhibit outstanding optical properties that are not necessarily shared by their epitaxially grown counterparts. The great versatility associated to the chemical route also offers realistic prospects for using such nanoparticles in devices, including an easy integration in photonic structures and photonic circuits. The Phocos group in INSP has started a research program devoted to the study of perovskite emitters that were re-discovered at the nanometer scale a few years ago only. The studies aim to gain a fine understanding in the fundamental electronic, optical and magneto-optical properties of systems having various dimensionalities (dots, wires, platelets). A particular attention is paid to the relationship between the structural and environmental parameters (crystalline symmetries, level of confinement, shape anisotropy, dielectric confinement, charging state etc) and the fine structure of the band edge excitons so as to be able to characterize and optimize a single crystal-based quantum « platform » and be able to have it efficiently coupled to nanoguides or cavities. Dynamical properties (relaxation rates, multiexcitonic processes) as well as temporal coherence are complementary facets also explored by the team. At present time, our studies mainly consider fully inorganic, ternary metal-halide perovskite materials. The development of bright quantum sources with high repetition rate and ’high’ temperature working capabilities and their integration in larger quantum systems are among the priority issues.

[1] J. Ramade et al. ’Fine structure of excitons and electron–hole exchange energy in polymorphic CsPbBr3 single nanocrystals’, Nanoscale 10, 6393 (2018). ; [2] R. Ben Aich et al ’Bright-Exciton Splittings in Inorganic Cesium Lead Halide Perovskite Nanocrystals’, Phys. Rev. Applied 11, 034042 (2019) ; [3] M. Baranowski et al. ’Giant Fine Structure Splitting of the Bright Exciton in a Bulk MAPbBr3 Single Crystal’, Nano Lett. 19, 7054 (2019).

Keywords : Quantum emitters, Exciton fine structure, Nanophotonics, Perovskite nanocrystals

Image Caption : Micro-Photoluminescence spectroscopy of a single CsPbBr3 nanocrystal (emission spectrum and polarization diagram).

Contracts : ’Contrat ANR IPER-Nano2, 2018-2022’ ; Coordinator : M Chamarro (INSP) Ongoing collaborations :
 @INSP : ’Optoelectronics of Confined Nanomaterials’ team, E. Lhuillier (PHYSURF group)
 Outside INSP : (1) ’Nano Optics’ group, C Diederichs, C Voisin, Y. Chassagneux (LPENS - CNRS/Sorbonne Université) (2) ’Nano-Optics and Quantum Fluids of Light’ teams, Q. Glorieux & A. Bramati (Quantum Optics Group, LKB - CNRS/Sorbonne Université) (3) ’Physics Department, Laboratoire de Physique des Matériaux’, K. Boujdaria (Faculté des Sciences de Bizerte) (4) ’Quantum Electronics’ team, P. Plochocka (LNCMI, Toulouse)