Optical properties of phosphorescent nano‐silicon electrochemically doped with terbium

Abstract

AbstractHybrid thin films consisting of oxidized nano‐silicon doped with terbium have been fabricated. Nano‐silicon was formed by electrochemical etching of silicon wafers. Terbium was incorporated into nano‐silicon pores by electrochemical deposition. Different oxidizing thermal treatments were applied to the films. The samples treated by high‐pressure water vapor annealing (HWA) exhibited strong blue emission with a phosphorescent component, as previously reported by our group. The low temperature (260 °C) HWA also led to strong emission from Tb3+ ions, whereas typical high temperature (900 °C) treatment generally used to activate Tb3+ ions in silicon‐based materials led to less luminescent samples. Spectroscopic and dynamic analyses suggest that terbium was incorporated as a separate oxide phase in the pores of the porous nano‐silicon. The PL of the terbium phase and nano‐silicon phase exhibit different temperature and excitation power dependences suggesting little optical or electronic interaction between the two phases. The luminescence of terbium is better activated at low temperature (260 °C) than at high temperature (900 °C). The hybrid material may find some applications in photonics, for instance as a display material. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)