Wet chemical synthesis and spectroscopic study of CdHgTe nanocrystals with strong near-infrared luminescence

Several series of CdHgTe composite nanocrystals were prepared using a wet-chemical colloidal technique. The synthesis began using CdTe nanocrystal precursors stabilised using 1-mercapto-2,3-propanediol (1-thioglycerol) to which subsequent layers of HgTe and CdTe were added in an attempt to form both CdTe/HgTe core/shell and CdTe/HgTe/CdTe quantum dot quantum well (QDQW) structures. The room temperature photoluminescence (PL) spectra of the resulting hybrid nanocrystals all exhibited a significant increase in quantum efficiency (QE) over the pure CdTe material. In addition, the position of the ‘excitonic’ PL peak was red-shifted to the near infrared to give emission wavelengths ranging from 600 to 1350 nm depending on the composition. The possibility of alloying, and a redistribution of the mercury throughout the interior of the particles is discussed, along with the high resolution transmission electron microscopy (HRTEM) of some selected samples.