Characterization of photonic dots in Si/SiO2 thin-film structures

We have studied bright electroluminescent dots on a single SiO2 layer and o n Si/SiO2 layer pairs prepared by chemical-vapor deposition onto the silico n wafer substrate. The size, density, and brightness distribution of the do ts and the fractal dimension of the light maps have been characterized usin g charge-coupled-device (CCD) camera techniques, which allow reliable quant itative analysis. We have found that the fractal dimension of the light map s depends on the structure of the first silicon dioxide layer. CCD images a nd atomic-force microscope and scanning tunneling microscopy analysis have been compared in order to find a spatial correlation between the dots and t he surface morphology or electrical properties of the thin films, but no co rrespondence was found, indicating that the origin of the dots must be in t he interface between the silicon substrate and the first oxide layer. We ha ve also shown that the dots are not related to heating of the sample. (C) 2 001 American Institute of Physics.