Structural and optical properties of oxidized porous silicon layers activated by Zn2SiO4 : Mn2+

Zn2SiO4:Mn2+ crystalline particles were grown into oxidized porous silicon layers by chemical impregnation of porous silicon. The size of particles is about 150 nm, with slight alignment in the direction of pores. X-ray mapping data and decay time measurements demonstrate that segregated Zn2SiO4:Mn2+ particles have formed inside an oxidized porous silicon structure. The layers emit green luminescence, which comes from the Zn2SiO4:Mn2+ particles embedded in the porous layer. The oxidation of Si skeleton makes it transparent to the luminescence light. The pore size and skeleton size of the processed layers were found almost two times larger than the starting porous silicon layers. Impregnation was found almost uniform in depth, i.e., 24% deviation from average. The luminescence decay time decreases with increasing Mn content. At low temperature, the decay curves show a saturating trend, while at higher temperatures this trend is less observable. These results can be explained using a model which accounts for the contribution of traps to the luminescence. The double exponential function which results from the model can well fit the decay curves.