Preparation of Si Nanocrystals Using Anodic Porous Alumina Template Formed on Silicon Substrate

A novel technique to extend template application of anodic porous alumina to Si has been reported. First, porous alumina template about 400nm thick was prepared on silicon substrate by anodizing thin aluminum film with high purity of 99.99% in 15 wt.% sulfuric acid under a constant voltage of 20 V and at an electrolyte temperature of 5^oC. Then, amorphous Si layer approximately 50nm in thickness was deposited onto the surface of template by using electron beam evaporation technique followed by an Xe ion beam bombardment, upon which as-coated Si layer at the pore mouth could be removed into pores smoothly. Three runs were performed by repeating above process of deposition and post bombardment. Finally, samples were annealed at 800^oC for 30min in nitrogen. Transmission electron microscopy and x-ray diffraction analysis reveal Si nanocrystals with a size of 15-20nm being formed in the pores of template.