Electroluminescence from HgTe Nanocrystals and Its Use for Active Imaging
Junling Qu, Prachi Rastogi, Charlie Gréboval, Delphine Lagarde, Audrey Chu, Corentin Dabard, Adrien Khalili, Hervé Cruguel, Cédric Robert, Xiang Xu, Sandrine Ithurria, Mathieu G. Silly, Simon Ferré, X. Marie, Emmanuel Lhuillier
Abstract
Mercury telluride (HgTe) nanocrystals are among the most versatile infrared (IR) materials with the absorption of lowest energy optical absorption which can be tuned from the visible to the terahertz range. Therefore, they have been extensively considered as near IR emitters and as absorbers for low-cost IR detectors. However, the electroluminescence of HgTe remains poorly investigated despite its ability to go toward longer wavelengths compared to traditional lead sulfide (PbS). Here, we demonstrate a light-emitting diode (LED) based on an indium tin oxide (ITO)/zinc oxide (ZnO)/ZnO-HgTe/PbS/gold-stacked structure, where the emitting layer consists of a ZnO/HgTe bulk heterojunction which drives the charge balance in the system. This LED has low turn-on voltage, long lifetime, and high brightness. Finally, we conduct short wavelength infrared (SWIR) active imaging, where illumination is obtained from a HgTe NC-based LED, and demonstrate moisture detection.