Structural characterization of ZnO/ Er2O3 core/shell nanowires

Erbium-Doped Mixed Oxide Nanowires of Zinc and Germanium: Role of Host Structure on Near Infrared Emission

“…Beyond this value, the Er 3+ near-IR PL intensity diminishes, as presumably the ZnO host does not permit facile insertion of the Er 3+ impurity centers into polar Zn–O bonds . Previous studies on Er 3+ surface enriched ZnO nanowires and ZnO tetrapod structures are consistent with this observation. , …”

“…8 Previous studies on Er 3+ surface enriched ZnO nanowires and ZnO tetrapod structures are consistent with this observation. 12,13 For example, the introduction of a surface Ge layer, subsequently transformed to a Zn 2 GeO 4 phase by annealing, onto Er-doped ZnO tetrapods produces superior near-IR emission relative to similarly annealed Er-doped ZnO tetrapod structures; this is presumably a function of more facile Er 3+ insertion into the germanium-containing oxide framework. 13 Er 3+ Concentration.…”

Coordination of Eu3+ Activators in ZnAlEu Layered Double Hydroxides Intercalated by Isophthalate and Nitrilotriacetate

“… 13 − 17 However, while the wavelength of the 4f–4f spectral lines of trivalent rare-earth (RE 3+ ) elements changes only a few nanometers when different matrices are compared, the relative intensity of their emission lines can be significantly modified by the crystal field, as described by the Judd–Ofelt theory. 18 − 27 According to this theory, the RE 3+ 4f–4f transition probabilities are dependent on a set of three intensity parameters (Ω 2 , Ω 4 , and Ω 6 ), which depends on the odd components of the crystal-field potential. In general, Ω 2 is most affected by angular changes of the ligating atoms around the RE 3+ , while Ω 4 and Ω 6 are more sensitive to radial changes and the polarizability of the groups coordinating to the RE 3+ .…”

“…Rare-earth (RE) elements are known for presenting unique luminescence properties attributed especially to their narrow emission lines and weak dependence of the emitted wavelengths to the host matrix. The explanation of these features resides in the shielding of the optically active partially filled 4f energy levels of the lanthanides provided by the completely filled external 5s 2 and 5p 6 subshells. − However, while the wavelength of the 4f–4f spectral lines of trivalent rare-earth (RE 3+ ) elements changes only a few nanometers when different matrices are compared, the relative intensity of their emission lines can be significantly modified by the crystal field, as described by the Judd–Ofelt theory. − According to this theory, the RE 3+ 4f–4f transition probabilities are dependent on a set of three intensity parameters (Ω 2 , Ω 4 , and Ω 6 ), which depends on the odd components of the crystal-field potential. In general, Ω 2 is most affected by angular changes of the ligating atoms around the RE 3+ , while Ω 4 and Ω 6 are more sensitive to radial changes and the polarizability of the groups coordinating to the RE 3+ .…”

Gold Core–Semiconductor Shell Nanowires Prepared by Lithographically Patterned Nanowire Electrodeposition

“…Core–shell nanowires have been synthesized from a variety of materials to take advantage of the enhanced properties over their single-material counterparts. For instance, core–shell nanowires have been used to prepare a variety of devices, including lasers and light-emitting diodes, − field-effect transistors, − and solar cells, − that either would not work or would be inefficient if prepared from single-material nanowires. However, the majority of the work on core–shell nanowires has focused on semiconductor/semiconductor nanowires, with very few reports on metal/semiconductor core/shell nanowires − despite the unique properties demonstrated by metal/semiconductor heterostructures.…”