Eur. Phys. J. D 34, 139-143 (2005)
https://doi.org/10.1140/epjd/e2005-00104-y

Rare earth based clusters for nanoscale light source

¹ Laboratoire de Physique de la Matière Condensée et Nanostructures, Université Claude Bernard-Lyon1 et CNRS UMR 5586, Bâtiment Léon Brillouin, 6 rue Ampère, Domaine scientifique de la Doua, 69622 Villeurbanne Cedex, France
² Laboratoire de Physico-chimie des matériaux luminescents, Université Claude Bernard-Lyon1 et CNRS UMR 5620, Bâtiment Alfred Kastler, 10 rue Ampère, Domaine scientifique de la Doua, 69622 Villeurbanne Cedex, France
³ Laboratoire de Spectrométrie Ionique et Moléculaire, Université Claude Bernard-Lyon1 et CNRS UMR 5620, Bâtiment Alfred Kastler, 10 rue Ampère, Domaine scientifique de la Doua, 69622 Villeurbanne Cedex, France

Corresponding author: ^a Bruno.Masenelli@lpmcn.univ-lyon1.fr

Received: 6 September 2004
Published online: 13 July 2005

Abstract

We investigate the fundamental properties of films resulting from the deposition of Eu³⁺ doped Gd₂O₃ clusters. We first report that the crystalline structure of clusters with diameter as low as 2.8 nm is still BCC (as in the bulk phase at ambient temperature and pressure). No phase transition to monoclinic structure is observed. We show that contamination from air (formation of hydroxide) is important and leads to the modification of the luminescence of the Eu³⁺ ions. Furthermore, films protected from this contamination have been fabricated and show a new feature (broad peak at 625 nm). It means that contamination is not the only mechanism responsible for the modification of the light emission spectrum. The crystal field symmetry breaking induced by the surface also plays a major role. Eventually, we show that the widening of the optical gap continues for these very small clusters. We discuss this effect in the frame of the quantum confinement model.