3-DIMENSIONAL PHONON CONFINEMENT IN CDSE MICROCRYSTALLITES IN GLASS

Results are presented which demonstrate the existence of unambiguous t hree-dimensional quantum confinement of phonons within crystallites of the Il-VI semiconductor CdSe, which were prepared by the method of di ffusive growth within a doped glass matrix. The confinement was invest igated by means of Raman scattering from zone centre longitudinal opti cal (Lo) phonons. These Raman spectra illustrate Lo phonon peaks showi ng a low-energy shift and broadening with decreasing crystallite size. The experimental measurements are compared with a theoretical model o f phonon confinement which includes a size distribution parameter. The experimental results are in good agreement with the predictions of th is model. Surface vibrational modes and the effects of hydrostatic pre ssure from the glass matrix do not appear to be of significance in the samples investigated.