OPTICAL PROPERTIES OF CdS AND Se CLUSTERS IN ZEOLITES

Abstract

We have studied the electronic and vibrational properties of CdS and Se clusters in zeolites by Raman scattering and photoluminescence measurements. CdS clusters were formed photochemically through the dissociation of S 8 molecules in A and X types of Cd 2+-exchanged zeolites by laser irradiation, while CdSe clusters were not successfully produced in the same manner. The 1LO mode of CdS at 300 cm −1 shifts to lower frequencies in the zeolites in comparison with that of bulk CdS , indicating the effect of phonon confinement. Se clusters incorporated into zeolites with different pore sizes (3A, 4A, 5A, and 13X) exhibit strong dependence of the structural phase stability and the structural unit on the geometrical constraints of zeolites.

Optical Properties of Selenium Clusters/Particles Incorporated into Porous Materials

“…ahn versus photon energy hn for Se clusters incorporated into a) LTA zeolites and b) FAU zeolites, together with that for bulk a-Se; a is the absorption coefficient in each zeolite. We have found by Raman scattering measurements and reported that the structure of Se clusters is intriguingly affected by the geometrical restriction in the zeolites [9,10]. Se clusters in 3A(K + ) have a helical chain structure or chain-like segment (i.e.…”