Extended quantum confinement luminescence center model for photoluminescence from oxidized porous silicon and nanometer-Si-particle- or nanometer-Ge-particle-embedded silicon oxide films

Through analysis of the latest experimental results reported in the literat ure and obtained in our laboratory, we have extended our previous quantum c onfinement/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 the re are three main types of competitive photoexcitation/photoemission proces ses and that the process in which photoexcitation occurs in the nanometer s ilicon particles (NSPs) while photoemission occurs in the luminescence cent ers (LCs) in the SiOx layers very close to the NSPs is usually the major on e. We discuss under what conditions the other two types of processes will d ominate. We believe that the extended quantum confinement/luminescence cent er model is a physical model that is suitable for the photoluminescence fro m silicon oxide films embedded with NSPs or nanometer Ge particles (NGPs), as well as from oxidized porous Si. (C) 1999 Elsevier Science Ltd.