材料期刊网

Through analysis of the latest experimental results reported in the literature and obtained in our laboratory, we have extended our previous quantum confinement/luminescence center model for the photoluminescence mechanism of porous Si and of nanometer-silicon-particle-embedded Si oxide films (G.G. Qin and Y.Q. Jia, Solid State Commun. 86, 559 (1993)). We consider that there are three main types of competitive photoexcitation/photoemission processes and that the process in which photoexcitation occurs in the nanometer silicon particles (NSPs) while photoemission occurs in the luminescence centers (LCs) in the SiOx layers very close to the NSPs is usually the major one. We discuss under what conditions the other two types of processes will dominate. We believe that the extended quantum confinement/luminescence center model is a physical model that is suitable for the photoluminescence from silicon oxide films embedded with NSPs or nanometer Ge particles (NGPs), as well as from oxidized porous Si. (C) 1999 Elsevier Science Ltd.