WIDTH OF THE EXCITONIC ABSORPTION PEAK AND SIZE OF CDSXSE1-X SEMICONDUCTOR NANOCRYSTALLITES

Confinement effects are observed in CdSxSe1-x semiconductor nanocristallites ('quantum dots') in a borosilicate glass. The absorption spectra are measured at 4.5 and 300 K. The width of the first excitonic peak was recorded as a function of particle sizes between 2 and 7.6 nm. these sizes being determined by low frequency inelastic Raman scattering (LOFIRS). The smallest width of the first excitonic absorption peak was observed for particles with a radius a = 2 nm. It is further shown from Raman scattering that the composition of the nanocrystallites remains constant (x = 0.25) during their growth.