In situ luminescence and IR study of porous silicon during and after anodic oxidation

• Published in: Thin solid films 1995-01, Vol.255 (1), p.87-91
• Main Authors: Dubin, V.M., Ozanam, F., Chazalviel, J.-N.
• Format: Article
• Language: English
• Subjects: Anodic oxidation; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Elemental semiconductors and insulators; Exact sciences and technology; Infrared spectroscopy; Luminescence; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Silicon
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/0040-6090(94)05678-7

When porous silicon is transferred into a non-fluoride electrolyte and anodically oxidized, the onset of red electroluminescence during anodic oxidation appears correlated with a decrease in the OH IR absorption bands, indicating significant electrolyte removal from the pores. The electron states whose population is affected by carrier injection or light excitation have been investigated using in situ electromodulated or photomodulated IR spectroscopy. The modulated IR absorption of red-luminescent electro-oxidized porous silicon exhibits an extra absorption of localized carriers in the 1000–2500 cm −1 region, suggesting that the red luminescence occurs through carriers trapped in localized states. The localization process may be efficiently affected by the dielectric constant of the medium surrounding the silicon nanocrystallites.