Physics of Low-Dimensional Structure vol:3-4 pages:51-60
The evolution of absorption, photoluminescence and Raman spectra of CdTe nanocrystals embedded in germanate glass under heat treatment has been studied. Two stages of the transformation of absorption spectrum at the isothermal annealing were observed. During the first stage the absorption peak forms, whereas during the second stage the peak position shifts to lower energy as annealing time increases. Time dependences of the nanocrystals average size were recovered from absorption spectra using the tight-binding model. It was found that at the second stage the average size changed very slowly, as R similar to t(0.12-0.16). Similar behavior was found from photoluminescence and Raman (Lamb's mode position) spectra as well. That behavior is unusual for nanocrystals embedded in glass, and it reflects some peculiarity of the growth kinetics in the system studied. The presence of tellurium droplets ensemble in the glass matrix additionally to the CdTe nanocrystals ensemble, and the interaction of these ensembles through the diffusion field is supposed to be the reason of the observed temporal behavior.