PHOTOLUMINESCENCE, COMPOSITION AND MICROSTRUCTURE OF POROUS SILICON PREPARED BY DIFFERENT SUBSTRATES

Abstract

In this paper, the microstructure of porous silicon was discussed by scanning electron microscopy and Raman spectra. The compositions of the samples were studied by X-ray diffraction and electron diffraction. The luminescent properties of porous silicon were explored by the PL measurements. The results showed that the structure of the top porous silicon prepared by epitaxial silicon consists of meso-pores and that of the underlying porous silicon consists of macro-pores. Furthermore, the structure of porous silicon prepared by heavily doped silicon is made of nano-pores. The composition of porous silicon consists of the single-crystal phase, poly-crystal phase and amorphous-crystal phase, respectively. In addition, the luminescence of porous silicon may come from the defects on the silicon-rod surface and in Si complexes including siloxene, Si oxide and Si hydrides, and may not be related to amorphous phase and nano-phase.