CD1-YMNYS NANOPARTICLES - ABSORPTION AND PHOTOLUMINESCENCE PROPERTIES

In this paper we demonstrate that the use of colloidal assemblies perm its to control independently the size and composition of Cd1-yMnyS nan osized particles. As expected, for a given composition, the increase i n the band-edge energy with decreasing the particle size is observed a nd attributed to a quantum size effect. For a similar average particle size, the band gap does not vary linearly when manganese concentratio n increases. The minimum is more pronounced and its depth increases wi th decreasing the particle size. This is attributed to a quantum size effect and due to strong interactions between manganese ions and the c onduction and valence bands electrons. For similar size of nanocrystal s, the photoluminescence due to isolated Mn2+ ions in Cd1-yMnyS nanocl usters is observed when the particles are aged and the CdS trap emissi on is observed immediately after the synthesis. The most important par ameter in order to observe the Mn2+ ions luminescence is the aging tim e of the particles and not a quantum size effect as claimed previously . (C) 1998 Elsevier Science B.V. All rights reserved.