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. (C) 2000 Elsevier Science S.A. All rights reserved.