Transferring the nanocrystals (NCs) from the laboratory environment toward practical applications has raised new challenges. In the case of NCs for display and lightning, the focus was on reduced Auger recombination and maintaining luminescence at high temperatures. When it comes to infrared sensing, narrow band gap materials are required and HgTe appears as the most spectrally tunable platform. Its low-temperature synthesis reduces the growth energy cost yet also favors sintering. As a result, once coupled to a read-out circuit, the Joule effect aggregates the particles leading to a poorly defined optical edge and dramatically large dark current. Here, we demonstrate that CdS shells bring the expected thermal stability (no redshift upon annealing, reduced tendency to form amalgams and preservation of photoconduction after an atomic layer deposition process). The peculiar electronic structure of these confined particles is unveiled using k.p self-consistent simulations showing a significant exciton biding energy at around 200 meV. After shelling, the material displays a p-type behavior that favors the generation of photoconductive gain. The latter is then used to increase the external quantum
@article{arxiv.2402.13745,
title = {Infrared Imaging using thermally stable HgTe/CdS nanocrystals},
author = {Huichen Zhang and Yoann Prado and Rodolphe Alchaar and Henri Lehouelleur and Mariarosa Cavallo and Tung Huu Dang and Adrien Khalili and Erwan Bossavit and Corentin Dabard and Nicolas Ledos and Mathieu G Silly and Ali Madouri and Daniele Fournier and James K. Utterback and Debora Pierucci and Victor Parahyba and Pierre Potet and David Darson and Sandrine Ithurria and Bartłomiej Szafran and Benjamin T. Diroll and Juan I. Climente and Emmanuel Lhuillier},
journal= {arXiv preprint arXiv:2402.13745},
year = {2024}
}