Raman study of insulating and conductive ZnO:(Al, Mn) thin films

Cerqueira, M. F.; Viseu, Teresa; Campos, J.; Rolo, Anabela G.; Lacerda-Arôso, T. de; Oliveira, Filipe; Radović, Iva Bogdanović; Alves, E.; Vasilevskiy, Mikhail

doi:10.1002/pssa.201532162

Cited by 17 publications

(12 citation statements)

References 47 publications

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“…Additionally, the peak at 1356 cm −1 is associated with the vibration of carbon atoms (D band). Accordingly, the phonon frequencies of the Raman spectra attributed to ZnO are: 332 cm −1 (multiple-phonon scattering processes), 379 cm −1 (A1(TO)), 438 cm −1 (E2(high)), 483 cm −1 (2LA), 574 cm −1 (A1(LO)), and 663 cm −1 (TA+A1(LO)); which are in agreement with the literature [30,33,34,35], with the E2(high) mode at 438 cm −1 exhibitingthe strongest intensity. The rest peaks shown in the Raman spectrum of Figure 3 can be matched to the PLA of the materials.…”

Section: Resultssupporting

confidence: 91%

Electrochemistry Studies of Hydrothermally Grown ZnO on 3D-Printed Graphene

Vernardou

Kenanakis

2019

Nanomaterials

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A three-dimensional (3D) printer was utilised for the three-dimensional production of graphene-based pyramids and an efficient hydrothermal procedure for ZnO growth. In particular, the 3D-printed graphene pyramids were forwarded in Pyrex glass bottles with autoclavable screw caps filled with 50 mL of an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine for 1 h at 95 °C; sufficient enough time to deposit well-dispersed nanoparticles. X-ray diffraction patterns were in accordance with a Raman analysis and presented the characteristic peaks of graphite along with those of wurtzite ZnO. Different positions on the sample were tested, confirming the uniform dispersion of ZnO on graphene pyramids. From the electrochemical studies, it was found that the charging and discharging processes are affected by the presence of ZnO, indicating one well-defined plateau for each process compared to the previously reported bare graphene pyramids. In total, the material shows a value of 325 mAh g−1, a capacitance retention factor of 92% after 5000 scans, and a coulombic efficiency of 100% for the first scan that drops to 85% for the 5000th scan. This excellent performance is the result of the effect of ZnO and graphene that combines two Li+ accommodation sites, and the contribution of graphene pyramids, which provides more available sites to favor lithium storage capacity. Hence, this anode may be a promising electrode material for lithium-ion batteries.

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Section: Resultssupporting

confidence: 91%

Electrochemistry Studies of Hydrothermally Grown ZnO on 3D-Printed Graphene

Vernardou

Kenanakis

2019

Nanomaterials

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“…The spectrum shows two basic phonon modes of the hexagonal wurtzite phase ZnO at 434 and 567 cm −1 , which represents the E 2 H and A 1 LO , respectively. The E 2 H is associated with the vibration of oxygen atoms and can be related to the degree of crystallization whereas A 1 LO band is associated with the defects such as oxygen deficiencies, zinc interstitial, or their complexes [ 49 , 50 ]. The band at 327 cm −1 and 1134 cm −1 represent the multi-phonon scattering processes of ZnO [ 51 ].…”

Section: Resultsmentioning

confidence: 99%

Design of Alginate-Based Bionanocomposites with Electrical Conductivity for Active Food Packaging

Alves

Ferreira

Mendo

et al. 2021

IJMS

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Bionanocomposite materials have been designed as a promising route to enhance biopolymer properties, especially for food packaging application. The present study reports the preparation of bionanocomposite films of alginate with different loadings of pure reduced graphene oxide (rGO) or of mixed zinc oxide-rGO (ZnO-rGO) fillers by solvent casting. Sepiolite is used to make compatible rGO with the hydrophilic matrix. The addition of fillers to alginate matrix maintains the low water solubility promoted by the calcium chloride treatment, and, additionally, they demonstrate a weaker mechanical properties, and a slight increase in water vapor permeability and wettability. Due to the properties of ZnO-rGO, the alginate bionanocomposites show an increase of electrical conductivity with the increase of filler content. While the highest electrical conductivity (0.1 S/m) is achieved by the in-plane measurement, it is in the through-plane measurement the remarkable enhancement of almost 30 times greater than the alginate film. With 50% of ZnO-rGO filler, the bionanocomposites present the highest antioxidant and antibacterial activities. The combination of electrical conductivity with bioactive properties makes these films promising not only to extend food shelf-life but also to allow packaged food sterilization at low temperature.

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“…In this context, high quality layers of ZnO have been grown and evaluated mainly via vapor phase techniques such as molecular beam epitaxy (MBE), metal-organic chemical vapor deposition (MOCVD), and RF-sputtering [30][31][32]. However, these growth or deposition methods are very expensive and are not flexible as far as growth conditions are concerned.…”

Section: Introductionmentioning

confidence: 99%

Improved photoluminescence emission and gas sensor properties of ZnO thin films

Berger

Moura

Oliveira

et al. 2016

Ceramics International

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In this article, we report a comparative study of the influence of pressure-assisted (1.72 MPa) versus ambient pressure thermal annealing on both ZnO thin films treated at 330°C for 32 h. The effects of pressure on the structural, morphological, optical, and gas sensor properties of these thin films were investigated. The results show that partial preferential orientation of the wurtzite-structure ZnO thin films in the [002] or [101] planes is induced based on the thermal annealing conditions used (i.e., pressure assisted or ambient pressure). UV-vis absorption measurements revealed a negligible variation in the optical -band gap values for the both ZnO thin films. Consequently, it is deduced that the ZnO thin films exhibit different distortions of the tetrahedral [ZnO 4 ] clusters, corresponding to different concentrations of deep and shallow level defects in both samples. This difference induced a variation of the interface/bulk-surface, which might be responsible for the enhanced optical and gas sensor properties of the pressure-assisted thermally annealed film. Additionally, pressure-assisted thermal annealing of the ZnO films improved the H 2 sensitivity by a factor of two.

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Raman study of insulating and conductive ZnO:(Al, Mn) thin films

Cited by 17 publications

References 47 publications

Electrochemistry Studies of Hydrothermally Grown ZnO on 3D-Printed Graphene

Electrochemistry Studies of Hydrothermally Grown ZnO on 3D-Printed Graphene

Design of Alginate-Based Bionanocomposites with Electrical Conductivity for Active Food Packaging

Improved photoluminescence emission and gas sensor properties of ZnO thin films

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