Effects of rare earth impurities on the photoluminescence spectra of p‐type porous silicon

Abstract

Two process were used to incorporate Eu and Tb respectively on the porous silicon (PS) samples. First, samples were anodized in HF + IPA during 3 minutes; the samples were then washed and dried. A solution of the salts in water was deposited onto the samples' surface. The samples were heated until the solvent was evaporated and then the anodizing process continued for another three minutes. In the second method the anodizing process was carried out using an electrolyte composed of a mixture of the respective salt diluted in water, HF and IPA. The presence of Eu or Tb on the PS was confirmed by photoluminescence spectra taken in the visible region. The photoluminescence spectrum of samples present a wide background, characteristic of porous silicon and some electronic transitions corresponding to the Eu3+ or Tb3+ ion. Results show that it is possible to incorporate rare earth ions in PS samples at low temperature annealing (60 °C) during anodization process. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)