Photoinduced phenomena in nanostructured porous silicon

• Published in: Thin solid films 2006-07, Vol.510 (1), p.169-174
• Main Authors: Arce, R.D., Koropecki, R.R., Olmos, G., Gennaro, A.M., Schmidt, J.A.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electron paramagnetic resonance; Exact sciences and technology; Materials science; Nanostructures; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; Silicon; Surface treatments
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2005.08.376

In this work we study the evolution of porous silicon photoluminescence under illumination. Samples were obtained by electrochemical etching of crystalline silicon wafers of different types. For the p-type samples the evolution of the spectra is explained in terms of photoinduced oxidation of nanostructures, which in turns leads to a discrete change in the photoluminescence spectra, as we reported in previous works. For the n-type material, a progressive decrease of the luminescence intensity is observed, which is attributed to the photoinduced generation of dangling bond related defect states at the surface layer surrounding the nanostructures. This model explains qualitatively well the kinetics of the evolution of the measured photoluminescence. Preliminary results of electronic paramagnetic resonance spectroscopy agree with this model.