Porous silicon morphological characteristics

In some applications, porous silicon (PSi) is, however, desired to increase the specific surface area (up to 1000 mVcm ). Several books and reviews have been already published about PSi formation mechanisms, morphologies and optical properties (cf [130-133]). Briefly, PSi is usually prepared from (100) Si wafers by constant-current anodization in an ethanolic solution (mixture of HF with ethanol). The characteristics of the pores are determined by the doping of the substrate, the HF concentration and the cturent density used during the anodization process [134-139]. PSi surfaces present =Si-H, =SiH2> and trihydride (-SiHj) sites. Potential steric hindrances could appear most hkely when micropores formation is obtained. It should be mentioned that PSi received increasing interest in the 1990s because of its luminescence properties in the visible range. 

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