A series of intrazeolitic silicon nanoclusters prepared from different Si loadings are investigated by SiKandL2,3x-ray absorption near-edge structure, x-ray photoelectron and photoluminescence spectroscopies. They exhibit strong room-temperature photoluminescence in the yellow-orange region. It is found that the growth of Si clusters within the pores of zeolite Y is limited to an average size of about 75 Si atoms per unit cell. ©1997 American Institute of Physics.