Abstract
Process of diffusion controlled phase decomposition of oversaturated solid solution, which makes it possible to grow semiconductor nanocrystals in a glass matrix and to vary the size of them in a controlled manner, is reviewed. It is demonstrated that optical properties of semiconductor-doped glasses are governed by quantum confinement of electronic and vibronic excitations in the nanocrystals. Manifestations of the quantum size effect in absorption, luminescence and Raman scattering spectra of these composite materials are regarded.