Effect of material structure on photoluminescence spectra from silicon nanocrystals

The thickness of a silicon dioxide layer is shown to have a significant effect on the measured photoluminescence spectrum from silicon nanocrystals embedded in the layer. This can range from significant but subtle spectral distortions that are difficult to detect, including changes in intensity, peak position and peak width, to gross distortions that are readily apparent as a modulation of the measured spectrum. These distortions are shown to be a simple consequence of the wavelength dependent reflectivity of the sample structure but to have important implications for determining nanocrystal properties from such data.