Luminescent properties of nano-crystalline silicon films embedded in SiO2

Nano-crystalline silicon (nc-Si) films embedded in SiO2 exhibited strong visible light luminescence at room temperature. The energies of photoluminescence peak were found to be more than 1.9 eV and the peaks shifted to higher energies when nano-Si films were post-oxidized. The photoluminescence intensity depended significantly on the size of the grains and the characteristics of the oxidized surface. Microcrystalline silicon grains of 2-3 nm average size and radiation recombination centers located on the nanoscale silicon grain surfaces and located in the Si oxide layers are considered to be the source of the visible luminescence.