Morphological, optical and electrical characterization of antireflective porous silicon coatings for solar cells

Porous silicon (PS) layers are formed on multicrystalline silicon solar cel ls by chemically etching the emitter of these devices. Stain etched PS prov ides the simultaneous formation of a selective emitter and an antireflectiv e layer. The optical behavior of the antireflective coating over the solar spectrum is determined, resulting in very low values of the reflectance. Th e variation of the topography, as well as the grain size of the PS and the metallic contacts before and after PS formation, is analyzed by scanning el ectron microscopy (SEM) and atomic force microscopy (AFM). Furthermore, the electrical properties of both the emitter and the front metallic contacts are investigated. Finally, the effect of rapid thermal processing in nitrog en and oxygen atmospheres on the antireflective properties of the PS is stu died. (C) 2001 Elsevier Science B.V. All rights reserved.