100 À x)SiO 2 À xHfO 2 (x = 10, 20, 30 mol) glass–ceramics planar waveguides activated by 0.3 mol% Er 3+ ions were prepared by sol–gel route, using dip-coating deposition on v-SiO 2 substrates. High resolution transmission electron microscopy has shown that after an adapted heat treatment, the resulting materials show nanocrystalline structures. The glass–ceramics waveguides were characterized by m-line, Raman, losses measurements, and photoluminescence spectroscopy. Photoluminescence spectroscopy has demonstrated the embedding of erbium ions in the nanocrystals. The results are discussed with the aim of assessing the role of hafnia on the structural, optical and spectroscopic properties of erbium doped silica hafnia glass–ceramics planar waveguides.