|Authors:||Danny E. P. Vanpoucke, Shannon S. Nicley, Jorne Raymakers, Wouter Maes, and Ken Haenen|
|Journal:||Diam. Relat. Mater 94, 233-241 (2019)|
|Graphical Abstract: Spin polarization around the various Eu-defect models in diamond. Blue and red represent the up and down spin channels respectively.|
The incorporation of Eu into the diamond lattice is investigated in a combined theoretical-experimental study. The large size of the Eu ion induces a strain on the host lattice, which is minimal for the Eu-vacancy complex. The oxidation state of Eu is calculated to be 3+ for all defect models considered. In contrast, the total charge of the defect-complexes is shown to be negative: -1.5 to -2.3 electron. Hybrid-functional electronic-band-structures show the luminescence of the Eu defect to be strongly dependent on the local defect geometry. The 4-coordinated Eu substitutional dopant is the most promising candidate to present the typical Eu3+ luminescence, while the 6-coordinated Eu-vacancy complex is expected not to present any luminescent behaviour. Preliminary experimental results on the treatment of diamond films with Eu-containing precursor indicate the possible incorporation of Eu into diamond films treated by drop-casting. Changes in the PL spectrum, with the main luminescent peak shifting from approximately 614 nm to 611 nm after the growth plasma exposure, and the appearance of a shoulder peak at 625 nm indicate the potential incorporation. Drop-casting treatment with an electronegative polymer material was shown not to be necessary to observe the Eu signature following the plasma exposure, and increased the background
Oct 28 2014
Comment on ‘Europium doping induced symmetry deviation and its impact on the second harmonic generation of doped ZnO nanowires’
In Dhara et al. 2014 Nanotechnology 25 225202, the authors reported on the synthesis of Eu-doped ZnO nanowires (NWs) and investigated the influence of Eu doping on the second harmonic generation (SHG). Maximum SHG was found to correlate strongly with the structural deformation attributed to Eu3+ doping. In this comment, we show the deformation of interest is due to the presence of Eu2+ dopants, based on both the experimental data presented by Dhara et al. and ab-initio density functional theory calculations.