On the mechanism of photodegradation of porous silicon in oxygen-containing ambient

✍ Scribed by Saren, A. A. ;Kuznetsov, S. N. ;Pikulev, V. B. ;Gardin, Yu. E. ;Gurtov, V. A.

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 147 KB
• Volume: 202
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200461182

✦ Synopsis

Abstract

An explanation of the mechanism of porous silicon (PS) photodegradation in an oxygen‐containing ambient has been proposed. The specific oxidation of luminescent Si nanocrystallites in a porous layer occurs via an intermediate specie, namely ozone produced in oxygen under illumination over a wide range of photon energies. It is shown by photoluminescence (PL), electron spin resonance (ESR) and capacitance–voltage methods that ozone‐induced oxidation is accompanied by defect generation at the Si crystallite/oxide interface. Some of these centers act as a nonradiative drain for electron–hole pairs under PL excitation. As revealed by capacitance spectroscopy in an MOS structure with a porous sublayer, these defects constitute an interface states spectrum broadly spread through the silicon band gap. The above‐mentioned defects appear in ESR spectra as Pb‐like centers originated from incomplete passivation of silicon bonds with oxygen at the crystallite surface. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)