Influence of the permeable layer number of porous silicon microcavity on reflection spectrum

The influence of permeable layer number of porous silicon microcavity (PSM) on the reflectance spectrum has been carried out from both simulations and experiments. The increase of the effective refractive index of the first porous silicon (PS) layer of PSM will causes a blue shift for the reflectance spectrum. With one more layer refractive index increasing, the blue shift becomes less, and it will shift to a higher wavelength when the layer number becomes large enough. This study would be helpful for simple fabrication of highly sensitive, fast responsible biosensors based on the blue shift of reflectance spectrum, and such fabricated Au/PSM substrate of multilayer PS might have a potential to detect minor biomolecules by means of surface state effects.