Optical and structural investigation of ZnO@ZnS core–shell nanostructures

Flores, Efracio Mamani; Raubach, Cristiane W.; Gouvêa, Rogério Almeida; Longo, Elson; Cava, Sergio; Moreira, Mário L.

doi:10.1016/j.matchemphys.2016.02.022

Cited by 26 publications

(21 citation statements)

References 42 publications

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“…Thus, in Sundararajan et al [ 19 ] it was said that the Fourier‐transform infrared spectroscopy (FT‐IR) spectra confirmed starching vibrations of ZnO and ZnS, respectively. In Flores et al [ 20 ] the same conclusion was reached using Raman spectroscopy. No attention was paid to the possibility of the formation of any layer between the ZnO core and the ZnS shell, which is the topic of our research.…”

Section: Introductionsupporting

confidence: 54%

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Phonons investigation of ZnO@ZnS core‐shell nanostructures with active layer

Hadžić

Matović

Randjelovic

et al. 2020

J Raman Spectroscopy

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In the present work experimental study of the ZnO@ZnS core‐shell nanostructure with an active layer obtained by conversion of zinc oxide powders with H2S is reported. Тhe prepared structures were characterized by scanning electron microscopy, X‐ray diffraction, Raman spectroscopy, and far‐infrared spectroscopy. Top surface optical phonon (TSO) in ZnO, characteristic for the cylindrical nano‐objects, the surface optical phonon (SOP) mode of ZnS, and SOP modes in ZnO@ZnS core‐shell nanostructure are registered. Local mode of oxygen in ZnS and gap mode of sulfur in ZnO are also registered. This result is due to the existence of an active layer in the space between ZnO core and ZnS shell, which is very important for the application of these materials as thermoelectrics.

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Section: Introductionsupporting

confidence: 54%

“…[ 14–18 ] In previous studies of the ZnO@ZnS core‐shell structures, this phenomenon was disregarded. [ 19–24 ] So far, the research focus was on the methods of synthesis and the quality of the spatial homogeneity of the obtained structures, such are the attempts to eliminate the existence of impurity throughout the system.…”

Section: Introductionmentioning

confidence: 99%

Phonons investigation of ZnO@ZnS core‐shell nanostructures with active layer

Hadžić

Matović

Randjelovic

et al. 2020

J Raman Spectroscopy

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“…In the traditional approaches, ZnO/ZnS lms have been prepared by magnetron sputtering deposition, 8 and powders by the microwave-assisted solvothermal method. 9 Core/shell ZnO/ZnS nanowires have been obtained by sulfurizing ZnO nanowires using a vapor phase method under 23 torr and sulfur powder at a temperature of 190 C. 10 ZnO nanorods have been sulded by Na 2 S aqueous solution or immersed in alcoholic solutions of 2 nm ZnS quantum dots. 11 In other studies, ZnO nanobers have been covered by a ZnS shell during a gas-phase suldation reaction with hydrogen sulde 12 and sputtered ZnO lms have been coated or totally converted to ZnS lms by a suldation process.…”

Section: 5mentioning

confidence: 99%

“…In the traditional approaches, ZnO/ZnS films have been prepared by magnetron sputtering deposition, 8 and powders by the microwave-assisted solvothermal method. 9 Core/shell ZnO/ZnS nanowires have been obtained by sulfurizing ZnO nanowires using a vapor phase method under 23 torr and sulfur powder at a temperature of 190 °C. 10 ZnO nanorods have been sulfided by Na 2 S aqueous solution or immersed in alcoholic solutions of 2 nm ZnS quantum dots.…”

Section: Introductionmentioning

confidence: 99%

ZnS coating for enhanced environmental stability and improved properties of ZnO thin films

et al. 2018

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a Low environmental stability of ZnO nanostructures in hydrophilic systems is a crucial factor limiting their practical applications. ZnO nanomaterials need surface passivation with different water-insoluble compounds. This study describes a one-step passivation process of polycrystalline ZnO films with ZnS as a facile method of ZnO surface coating. A simple sulfidation reaction was carried out in gas-phase H 2 S and it resulted in formation of a ZnS thin layer on the ZnO surface. The ZnS layer not only inhibited the ZnO dissolving process in water but additionally improved its mechanical and electrical properties. After the passivation process, ZnO/ZnS films remained stable in water for over seven days. The electrical conductivity of the ZnO films increased about 500-fold as a result of surface defect passivation and the removal of oxygen molecules which can trap free carriers. The nanohardness and Young's modulus of the samples increased about 64% and 14%, respectively after the ZnS coating formation. Nanowear tests performed using nanoindentation methods revealed reduced values of surface displacements for the ZnO/ZnS system. Moreover, both ZnO and ZnO/ZnS films showed antimicrobial properties against Escherichia coli.

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“…Zinc oxide (ZnO) is used as a heterogeneous catalyst, have a high catalytic activity, nontoxic, insoluble, and also a cheap catalyst [3 -4] which is an important n-type [5][6][7] semiconductor. ZnO is not only a material of particular interest because of its unique optical and electronic properties, but also it has some characteristics that include the following: (a) wide-band gap semiconductor [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], (b) large exaction binding energy of 60 MeV [5-7, 10, 12, 13, 19-20]. The interest in ZnO is as a result of its high abundance and the availability of potentially high quality low cost substrate layers of transparent ZnO films on which electronic processes solar cells and flat panel displays occur [21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Impact of Post- Deposition Heat Treatment on the Morphology and Optical Properties of Zinc Oxide (ZnO) Thin Film Prepared by Spin-Coating Technique

Balogun¹

2017

JPMT

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This research work examines the structural and optical properties of ZnO thin films. Deposition were done by spin coating of solution of Zinc oxide onto pre-cleaned glass substrate at 4000 rpm for 30 sec using spin-coater under ambient condition at room temperature in order to form desired thickness of the film on the substrate. Post-deposition thermal annealing at different range of temperatures from 150°C to 600°C with steps of 50°C was carried out on the samples. The impact of thermal annealing on optical properties of the deposited thin film was investigated using UV-VIS spectrophotometer and scanning Electron Microscope for the morphology. The optical transmittance, reflectance, absorbance were recorded which was used to evaluate the optical band gap of Zinc oxide. Observation shows that band gap energy reduces as annealing temperature is increased from 150°C to 600°C. Observation made on the morphology using SEM model ASPEX 3020 showed that as the temperature increases the surface of the sample roughness increases. It was deduced that as the annealing temperature is increased the surface roughness increases. This may be due to increase in grain size with increase in annealing temperature. The band gap energy decreases as the annealing temperature increases.

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Optical and structural investigation of ZnO@ZnS core–shell nanostructures

Cited by 26 publications

References 42 publications

Phonons investigation of ZnO@ZnS core‐shell nanostructures with active layer

Phonons investigation of ZnO@ZnS core‐shell nanostructures with active layer

ZnS coating for enhanced environmental stability and improved properties of ZnO thin films

Impact of Post- Deposition Heat Treatment on the Morphology and Optical Properties of Zinc Oxide (ZnO) Thin Film Prepared by Spin-Coating Technique

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