Synthesis, Characterization and Oxidation Effects of Solid-State Reaction Silicon Nanocrystals

The unique synthesis of solid-state reaction silicon nanocrystals (Si nc) is reported. Different sizes of Si nc have been synthesized using mechanical milling at different milling hours. Using x-ray diffraction and Scherrer´s equation, the sizes of the Si nc synthesized are calculated to range from 10 nm to 25 nm. Transmission electron microscopic (TEM) images further verified the size derived from the diffraction results. These Si nc are also characterized using differential thermal analysis (DTA), raman scattering and infrared absorption. DTA and raman scattering reveals no amorphous Si content. At the same time, infrared absorption shows no trace of Si-H and Si-OH bonds. Further reduction of these solid-state reaction Si nc can be achieved by oxidation. 3 hours of annealing is capable of reducing Si nc from 12 nm to 8 nm. Self-limiting oxidation is experienced after 2 hours of oxidation which deters further size reduction.