It has been experimentally demonstrated that the indium tin oxide can be doped with rare earth element through the conventional sol-gel technique. Erbium in its trivalent state replaces the indium site in the indium tin oxide lattice. Homogeneously distributed and optically activated Er3+ ions then allow a strong photoluminescence emission at similar to 1.5 mu m. Reduced particle size and the existence of Sn are believed to affect the local structural environments of doped Er3+ ions, thus contributing to the radiative emission properties: Large spectral bandwidth without concentration quenching is useful for practical applications. (C) 2008 Elsevier B.V. All rights reserved.