Transformation of free-standing ZnO nanorods upon Er doping

Buryi, M.; Remeš, Z.; Babin, V.; Artemenko, Anna; Vaněček, V.; Dragounová, Kateřina; Landová, Lucie; Kučerková, Romana; Míčová, Júlia

doi:10.1016/j.apsusc.2021.150217

Cited by 23 publications

(42 citation statements)

References 67 publications

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“…However, a serious drawback of ZnO is the presence of large amount of intrinsic and extrinsic luminescent defects such as differently charged zinc or oxygen vacancies (V Zn,O ), zinc interstitials or impurities [ 11 , 12 , 16 , 17 ]. These luminescent centers either produce radiative emission bands within the about 1–2.4 eV [ 18 , 19 , 20 , 21 ] or contribute to non-radiative transitions. Moreover, the detailed analysis of ZnO based nanostructures via electron paramagnetic resonance (EPR) spectroscopy has provided information on the existence of Ga, Al or H shallow donors (SD) producing the typical EPR signal at g ≈ 1.96 [ 22 , 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

“…Molybdenum with the 3+–6+ row of charge states is an eligible candidate in this case since its improvement of the conductivity of ZnO:Mo nanorods and thin films has previously been observed [ 20 , 27 , 28 ]. In the past decade post-growth treatment, for example, annealing in air or exposure to hydrogen or oxygen plasma, has appeared the most efficient tool for the moderation of ZnO properties [ 13 , 14 , 19 , 20 , 21 , 29 , 30 , 31 , 32 ].…”

Section: Introductionmentioning

confidence: 99%

“…However, the effect of hydrogen and oxygen plasma treatment remained unknown and is addressed only in the current research. This is an important question since plasma treatment induced changes in the material phases present in the ZnO:Er nano- and microrods [ 21 ]. XPS analysis was carried out on the ZnO:Mo samples [ 33 ] confirming the presence of Mo on the surface of ZnO nanorods as Mo 6+ .…”

Section: Introductionmentioning

confidence: 99%

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Free-Standing ZnO:Mo Nanorods Exposed to Hydrogen or Oxygen Plasma: Influence on the Intrinsic and Extrinsic Defect States

et al. 2022

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Cationic doping of ZnO nanorods has gained increased interest as it can lead to the production of materials with improved luminescent properties, electrical conductivity and stability. We report on various Mo-doped ZnO powders of nanorods synthesized by the hydrothermal growth method. Further annealing or/and cold hydrogen or oxygen plasma modification was applied. The atomic structure of the as-grown and plasma-modified rods was characterized by X-ray diffraction. To identify any possible changes in morphology, scanning electron microscopy was used. Paramagnetic point defects were investigated by electron paramagnetic resonance. In particular, two new types of defects were initiated by the plasma treatment. Their appearance was explained, and corresponding mechanisms were proposed. The changes in the luminescence and scintillation properties were characterized by photo- and radioluminescence, respectively. Charge trapping phenomena were studied by thermally stimulated luminescence. Cold plasma treatment influenced the luminescence properties of ZnO:Mo structures. The contact with hydrogen lead to an approximately threefold increase in intensity of the ultraviolet exciton-related band peaking at ~3.24 eV, whereas the red band attributed to zinc vacancies (~1.97 eV) was suppressed compared to the as-grown samples. The exciton- and defect-related emission subsided after the treatment in oxygen plasma.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Free-Standing ZnO:Mo Nanorods Exposed to Hydrogen or Oxygen Plasma: Influence on the Intrinsic and Extrinsic Defect States

et al. 2022

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“…For example, the experimentally observed broad red bands ranging from 1 to 2 eV were related to zinc (VZn) or oxygen (VO) vacancies [5]. The red emission bands (1.8-2 eV) related to VZn [5,6] were recently also observed in the hydrothermally grown ZnO nano-and microrods [7,8]. It is known that low-level Mo doping (below 1%) can positively affect the luminescence properties of ZnO (both defect-related and exciton luminescence) [7,8], whereas doping with 10 and 30% of Mo deteriorates them.…”

Section: Introductionmentioning

confidence: 99%

“…ZnO structure can also be characterized by the typical electron paramagnetic resonance (EPR) single-line signal observed at the g factor g ≈ 1.96 ascribed to the shallow Ga, Al, H donors (SD) [9][10][11][12], the Zn + + D complex, D = Ga, Al, H [8]. The influence of Mo on this shallow donor was studied earlier [6,8] in the ZnO:Mo(0.05, 0.25, 1%) and ZnO:Mo(10, 30%). However, there is no systematic investigation of the influence of Mo at the doping level within 2-25% on ZnO structure, morphology and creation of zinc-molybdenum complex oxides, luminescence and magnetic properties.…”

Section: Introductionmentioning

confidence: 99%

Transformation of ZnO-based structures under heavy Mo doping: defect states and luminescence

Buryi

Remeš

Děcká

et al. 2021

NANOCON 2021 Conference Proeedings

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Hydrothermally grown ZnO-based structures were heavily doped with Mo (various doping levels from 2 to 25%). Mo was found to strongly affect the structure and morphology of ZnO, resulting in a complex mixture of zinc oxide and molybdenum. Moreover, the transformation of material phases upon the increased Mo content was observed. ZnO phase was observed only at low Mo doping level (2 and 5%). This correlated very well to the changes in the luminescence and electron paramagnetic resonance signals.

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Changes of Morphological, Optical, and Electrical Properties Induced by Hydrogen Plasma on (0001) ZnO Surface

Remeš

Artemenko

Ukraintsev

et al. 2021

Physica Status Solidi (a)

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Plasma provides specific adjustment of solid‐state surface properties offering an alternative to high temperature treatment. Herein, hydrogen plasma treatment of monocrystalline (0001) ZnO surface is studied in an inductively coupled plasma reactor with reduced capacitively coupled plasma mode. The crucial role of electrical grounding of the sample holder for plasma etching and related changes in the morphology, optical, and electrical properties of surfaces exposed to electron and ion bombardment are explained. The effects on the chemical composition of the surface are analyzed by X‐ray photoelectron spectroscopy (XPS), optical properties by photoluminescence spectroscopy, topography, roughness, and surface measurements by atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). All methods show altered ZnO surface properties before and after plasma treatment strongly depending on the electrical potential of the holder.

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Transformation of free-standing ZnO nanorods upon Er doping

Cited by 23 publications

References 67 publications

Free-Standing ZnO:Mo Nanorods Exposed to Hydrogen or Oxygen Plasma: Influence on the Intrinsic and Extrinsic Defect States

Free-Standing ZnO:Mo Nanorods Exposed to Hydrogen or Oxygen Plasma: Influence on the Intrinsic and Extrinsic Defect States

Transformation of ZnO-based structures under heavy Mo doping: defect states and luminescence

Changes of Morphological, Optical, and Electrical Properties Induced by Hydrogen Plasma on (0001) ZnO Surface

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