Investigation into the Growth Kinetics of CdTe Nanocrystals in Germanophosphate Glasses by Optical Spectroscopy

The evolution of the absorption, photoluminescence, and Raman spectra of germanophosphate glasses containing CdTe semiconductor nanocrystals is investigated. It is shown that two stages can be distinguished in the evolution of the absorption spectra during isothermal annealing. At the first stage, the annealing is accompanied by the appearance of the absorption peak. At the second stage, an increase in the heat treatment time leads to a shift in the absorption peak toward the short-wavelength range. The dependence of the mean size of nanocrystals is calculated within the tight-binding model. It is revealed that, at the second stage, the dependence of the mean size of CdTe nanocrystals formed in the germanophosphate matrix can be described by the relationship R ∼ t 0.12−0.16. This dependence is confirmed by the photoluminescence and Raman spectroscopic data (on the position of the Lamb mode).