Growth of luminescent Zn₂SiO₄:Mn₂₊ particles inside oxidized porous silicon: Emergence of yellow luminescence

Porous silicon layers were activated by the addition of Zn₂SiO₄:Mn²⁺ which resulted in green or yellow luminescent samples depending on the treatment conditions. The yellow peak occurs at 575 nm and has a considerably longer decay time than the green peak, which occurs at 525 nm. It is demonstrated that the yellow luminescence comes from small particles, typically 30 nm in size, which have been crystallized in the β-phase, while the green luminescence comes from the usual α-phase, which occurs with larger particles. β-Phase appears to be the dominant phase for small particles and any condition that results in the formation of small particles gives rise to yellow emission.