Luminescent spectroscopy and imaging of textured sprayed Er-doped ZnO films in the near ultraviolet and visible regions

• Published in: Journal of applied physics 2006-07, Vol.100 (1), p.014505-014505-7
• Main Authors: Bubendorff, J. L., Ebothé, J., El Hichou, A., Dounia, R., Addou, M.
• Format: Article
• Language: English
• Subjects: Condensed Matter; Materials Science; Physics
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.2211347

The textural dependence of the thermally sprayed Er-doped ZnO films on Er concentration is reported here. The [002] preferred growth orientation of hexagonal phase is obtained at the lower concentrations, while the [100] and [101] directions additionally raised from nearly 5 at. % Er content onwards. The cathodoluminescent characteristics of the samples in the near ultraviolet (UV) and visible region depict a complete extinction of the visible emitted bands ( λ = 445 , 526, and 665 nm ) at 1 at. % Er content. Their deactivation below this concentration is explained by a compensation of oxygen defects in the material due to the oxygen-rich medium of the deposition bath. Their reactivation beyond this particular concentration is ascribed to the increase of the Er + 3 ion shells whose internal radiative transitions lead to a recovering of these visible emitted bands. The radiative mechanism of the transitions from the ( F 9 ∕ 2 4 ) excited states to the ( I 15 ∕ 2 4 ) ground state, responsible for the λ = 665 nm emission, is predominant in that case. The respective normalized intensity of the violet ( λ = 445 nm ) and green ( λ = 526 nm ) emitted bands exhibits a maximal value for 3 at. % Er content, reaching a stabilized regime from about 5 at. % Er.