Doped Semiconductor Nanostructures Quantum Plasmonics – DIAAPASON

The discovery of Localized Surface Plasmon Resonance (LSPR) in doped semiconductor nanostructures ushered in a paradigm shift in plasmonics. Unlike metals, these nanostructures have lower and tunable free-carrier concentration, via impurity doping, resulting to tunable LSPR frequency and extending plasmonics to the IR range. Pushed to their ultimate dimensions, doped semiconductor nanocrystals are the perfect system to investigate the concept of plasmonicity at the nanoscale as the quantum confinement and the small number of carriers per nanostructure, both contribute to affect the collective carrier dynamics. The DIAAPASON project seeks to explore the boundary between classical and quantum plasmonics in these novel plasmonic materials, specifically doped silicon nanocrystals (SiNCs). To do so we will: (i) elaborate model systems made of assemblies of SiNCs of controlled small size and doping; (ii) measure their optical properties from the assembly level down to individual objects; and (iii) compare these measurements to time-dependent density-functional theory (TD-DFT) calculations. The coupling between state-of-the-art fabrication and doping methods, optical measurements and simulations will allow to address the impact of size reduction, few-electron regime, and their interplay on their plasmonic properties.
The consortium brings together 4 academic laboratories (from CNRS and CEA) and provides the requested complementarity, gathering experts of fabrication/doping of thin Si layers (LETI), elaboration of doped SiNCs (IJL) and metasurfaces (CEMES), optical spectroscopies (CEMES/IJL), atomic scale characterization (CEMES/IJL) and TD-DFT simulations (CiNaM).
Understanding and controlling the properties of these new plasmonic antennae as they are pushed to their ultimate dimensions paves the way for the realization of quantum-controlled devices fully compatible with CMOS technology.