LIGHT FROM SI-NANOPARTICLE SYSTEMS - A COMPREHENSIVE VIEW

Si in the form of finely divided crystalline particles with nanometer dimensions shows an efficient visible luminescence at room temperature . We examine the experimental facts for differently prepared nanoparti cle systems, such as electrochemically etched porous Si, layers and pa rticles synthesized from the gas phase and particles precipitated in a glassy SiO2-matrix after Si+-implantation. The observations preclude a simple interpretation of the light emission in terms of the physics of quantum dots. They also show it as unlikely that a single, specific molecular agent can account for the light. We provide a comprehensive view of the emission mechanism in which the luminescing Si is an inte ractive composite system with a crystalline core and a passivant mantl e layer of perturbed Si bonded to O and H. The predominant emission is via the electronic states of the perturbed Si. We note many similarit ies with the characteristics of luminescing a-Si:H.