Proceedings of nanoGe Fall Meeting 2018 (NFM18)
DOI: https://doi.org/10.29363/nanoge.nfm.2018.191
Publication date: 6th July 2018
Nanocrystals of heavily-doped semiconductors have recently emerged as very promising materials for plasmonics. In contrast to nanocrystals of noble metals, their Localized Surface Plasmon Resonance (LSPR) can be easily tuned in energy by controlling the carrier concentration through doping. In addition, due to the low concentration of carriers compared to metals, the LSPR can be extended to infrared and near-infrared ranges. Recent experimental studies have demonstrated the existence of LSPR in doped nanocrystals of Si and different types of oxides (ZnO, SnO2, In2O3). However, the physics of the LSPR in these NCs is not totally understood. In this talk, I will review recent theoretical studies performed to clarify a certain number of issues. The evolution with doping concentration of the optical processes from single-electron transitions to collective excitations will be described. The conditions required for the emergence of plasmonic modes will be discussed. The results of atomistic calculations will be compared with those of more classical approaches. The intrinsic mechanisms at the origin of plasmon damping in doped ZnO nanocrystals will be analyzed. In this case, the theoretical simulations show that the intrinsic line width of the LSPR can be below 80 meV, in agreement with recent experiments [1]. These results confirm that doped ZnO nanocrystals are very promising for the development of IR plasmonics.
[1] Delerue C. “Minimum Line Width of Surface Plasmon Resonance in Doped ZnO Nanocrystals”. Nano Letters 17 (12), 7599-7605 (2017).