Optically active centers in Eu implanted, Eu in situ doped GaN, and Eu doped GaN quantum dots

Journal Article · Sun Feb 15 04:00:00 EST 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3078783· OSTI ID:21190025

Bodiou, L; Braud, A; Doualan, J -L; Moncorge, R ^[1]; Park, J H; Munasinghe, C; Steckl, A J ^[2]; Lorenz, K; Alves, E ^[3]; Daudin, B ^[4]

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1. Centre de Recherche sur les Ions, les Materiaux et la Photonique (CIMAP), CNRS-CEA-ENSICAEN, Universite de Caen, UMR 6252, 14050 Caen (France)
2. University of Cincinnati, Cincinnati, Ohio 45221-0030 (United States)
3. Instituto Tecnologico e Nuclear, Estrada Nacional 10, PT-2685-953 Sacavem (Portugal)
4. INAC SP2M/PSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

A comparison is presented between Eu implanted and Eu in situ doped GaN thin films showing that two predominant Eu sites are optically active around 620 nm in both types of samples with below and above bandgap excitation. One of these sites, identified as a Ga substitutional site, is common to both types of Eu doped GaN samples despite the difference in the GaN film growth method and in the doping technique. High-resolution photoluminescence (PL) spectra under resonant excitation reveal that in all samples these two host-sensitized sites are in small amount compared to the majority of Eu ions which occupy isolated Ga substitutional sites and thus cannot be excited through the GaN host. The relative concentrations of the two predominant host-sensitized Eu sites are strongly affected by the annealing temperature for Eu implanted samples and by the group III element time opening in the molecular beam epitaxy growth. Red luminescence decay characteristics for the two Eu sites reveal different excitation paths. PL dynamics under above bandgap excitation indicate that Eu ions occupying a Ga substitutional site are either excited directly into the {sup 5}D{sub 0} level or into higher excited levels such as {sup 5}D{sub 1}, while Eu ions sitting in the other site are only directly excited into the {sup 5}D{sub 0} level. These differences are discussed in terms of the spectral overlap between the emission band of a nearby bound exciton and the absorption bands of Eu ions. The study of Eu doped GaN quantum dots reveals the existence of only one type of Eu site under above bandgap excitation, with Eu PL dynamics features similar to Eu ions in Ga substitutional sites.

• OSTI ID: 21190025
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 4 Vol. 105; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
ANNEALING
CRYSTAL GROWTH
DOPED MATERIALS
ENERGY GAP
EUROPIUM
EUROPIUM IONS
EXCITATION
EXCITED STATES
EXCITONS
GALLIUM NITRIDES
ION IMPLANTATION
MOLECULAR BEAM EPITAXY
PHOTOLUMINESCENCE
QUANTUM DOTS
SEMICONDUCTOR MATERIALS
THIN FILMS