  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
