Authors: M. Hajji^*, M. Ben Rabha, M. Khalifa, B. Bessaïs, H. Ezzaouia

Contact: Laboratoire de Photovoltaïque, Centre de Recherches et des Technologies de l’Energie, Technopole de Borj-Cédria, BP 95, 2050 Hammam-Lif, Tunisia

 e-mail: mhajji2001@yahoo.fr, Phone: +216 79325160, Fax: +216 79325825

Abstract

Porous silicon layers have been obtained by stain etching of multicrystalline silicon substrates in a HF/HNO₃ solution for different etching times. Atomic Force Microscopy (AFM) was used to analyze the morphology of the surface nanostructures. The photoluminescence and total reflectance of obtained porous silicon layers were measured. Obtained results show that the PSi nanostructure is largely affected by the elaboration conditions. For short etching times the porous surface reflectance reaches minimum values and the photoluminescence intensity attain maximum values. The gettering effect of porous silicon was also studied and related to its structural and optical properties. It is found that after thermal treatment of mc-silicon substrates with a thin porous layer on both sides in a N₂ atmosphere the effective minority carrier lifetime increases from 3 to about 47 μs.