Polymer-nanoparticle coatings on macroporous silicon matrix

We synthesized light-emitting coatings of CdS nanocrystals in polyethyleneimine and polyethyleneimine with multiwall carbon nanotubes on macroporous silicon. The photoluminescence of CdS nanocrystals in polyethyleneimine on oxidized macroporous Si is more intense in comparison with substrates c-Si, macroporous Si, and macroporous Si with a microporous layer, and is maximal for structures with maximal intensity of the local electric field at the Si-SiO2 interface. This indicates a significant decrease of non-radiative recombination in the CdS-polyethyleneimine layer due to electron flow from the silicon matrix to the nanocrystal layer. The photoluminescence of polyethyleneimine with carbon multiwall nanotubes on macroporous Si with a microporous layer is about six times more intense in comparison with substrates c-Si, macroporous Si and oxidized macroporous Si. This indicates a non-radiative proton recombination decrease due to hydrogen atoms on the boundary between Si matrix with micro