Optical and compositional characterisation of stain-etched porous silicon subjected to anodic oxidation and thermal treatments

In this work, we study optical and compositional properties of stain-etched porous silicon (PS) passivated by means of anodic oxidation or thermal treatments in a N-2 atmosphere. We search a passivation method that allows us to stabilise the surface properties of this material and to make it attractive to its implementation in a low-cost silicon-based solar cell fabrication process. We observe that the thermal treatment maintains the reflectance coefficient at very low values, and the anodic oxidation generates surfaces with a more homogeneous oxide composition than the thermal treatment. These results are appropriate with the requirements for future solar cells that can use these passivated porous layers as antireflection coatings. (C) 2003 Published by Elsevier Science B.V.