Research on Preparation of Porous Silicon Powders from Metallurgical Silicon Material

Stain etching, one step metal assisted chemical etching (1-MACE) and two-step metal assisted chemical etching (2-MACE) were used for preparing porous silicon powders (PSPs) based on metallurgical silicon powder. The influences of different oxidants species and concentrations on the structure of PSP were discussed. The results indicated that the different oxidant species has an important effect on the morphology and structure of PSP. In stain etching, there is still a challenge for fabricating PSP with uniform and controlled pore size structure. In contrast, metal-assisted chemical etching method is easier to prepare PSPs sample with uniform depth and pore size than stain etching, In 1-MACE, the growth rate of the PSPs pore was between 0.05 and 0.10 μm/min, which is far less than that of 2-MACE (about 0.2~0.5 μm/min). Furthermore, 2-MACE showed more advantages than stain etching and 1-MACE in controlling of pore size range and structure.