Effect of surface stresses on CuO nanowire growth in the thermal oxidation of copper

Mema, Rediola; Yuan, Lü; Du, Qingtian; Wang, Yiqian; Zhou, Guangwen

doi:10.1016/j.cplett.2011.07.012

Cited by 115 publications

(72 citation statements)

References 40 publications

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“…Copper oxide has many applications in areas like gas sensors, solar energy conversion cells, electronic cathode materials, semiconductors, and catalysts due to its electrical, optical, and catalytic properties (Darezereshki and Bakhtiari, 2011;Mema et al, 2011). Although various synthesis methods for preparing copper oxide are known, the thermal oxidation technique offers a simple, convenient, and fast method.…”

Section: Introductionmentioning

confidence: 99%

Leaching of Malachite Ore in Ammonium Sulfate Solutions and Production of Copper Oxide

Ekmekyapar

Demirkıran

Künkül

et al. 2015

Braz. J. Chem. Eng.

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-Malachite ore is one of the most important of oxidized copper ores. Copper production can be performed by using this ore. In this work, the leaching kinetics of malachite in ammonium sulfate solutions was investigated, and metallic copper was recovered by a cementation method from the resulting actual leach solution. Copper (II) oxide was prepared by an isothermal oxidation method from the cement copper. In the leaching experiments, the effects of reaction temperature, particle size, and stirring speed on copper leaching from malachite ore were studied. In the cementation experiments, metallic zinc was used as the reductant metal to recover the copper from the solution. Thermal oxidation of cement copper was performed under isothermal conditions. It was found that the leaching rate increased with increasing stirring speed and temperature, and decreased with particle size. It was observed that the leaching reaction fit to diffusion through the product layer. The activation energy of the leaching process was determined to be 25.4 kJ/mol. It was determined that the copper content of the metallic product obtained by the cementation method increased up to 96%. It was found that copper oxide prepared from cement copper had a tenorite structure.

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Section: Introductionmentioning

confidence: 99%

Leaching of Malachite Ore in Ammonium Sulfate Solutions and Production of Copper Oxide

Ekmekyapar

Demirkıran

Künkül

et al. 2015

Braz. J. Chem. Eng.

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show abstract

“…Most of the reports have suggested that a structure of CuO nanowires, a CuO layer, a Cu 2 O layer, and a Cu substrate (from the top to bottom) is formed through the process. The CuO layer has a small thickness and a small grain size compared with those of the Cu 2 O layer, of which the thickness is approximately 10-15 lm and the grains are large [31,32,53,54]. The Cu atoms in the substrate diffuse through grain boundary defects to the surface and form CuO nanowires through short-circuit diffusion [31].…”

Section: Resultsmentioning

confidence: 99%

“…The growth mechanism of CuO nanowires synthesized through the thermal oxidation of Cu foil has been discussed previously [30,31,[53][54][55][56]. Most of the reports have suggested that a structure of CuO nanowires, a CuO layer, a Cu 2 O layer, and a Cu substrate (from the top to bottom) is formed through the process.…”

Section: Resultsmentioning

confidence: 99%

Formation of urchin-like CuO structure through thermal oxidation and its field-emission lighting application

Chang

Hsu

Lin

et al. 2015

Journal of Alloys and Compounds

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“…Cross-section images (Figures 1(b) and 1(c)) reveal that obtained NWs are about 9 6 1 lm long and present tip and base diameters of 58 6 6 nm and 131 6 13 nm, respectively, where data are obtained from 30 NWs on the oxidized Cu foil and errors are given at a 95% confidence level. NW growth mechanism has been studied by other authors 18,[20][21][22] suggesting that CuO NW growth is based on Cu ion diffusion from the Cu foil through dislocations in the grain boundaries of a thick polycrystalline cuprous oxide (Cu 2 O) layer formed at an early stage of the thermal treatment. Since the growth mechanism is fed by the vertical diffusion of Cu ions along the NW in air ambient, some tapering effects can be expected.…”

mentioning

confidence: 99%

Fast response ZnO:Al/CuO nanowire/ZnO:Al heterostructure light sensors fabricated by dielectrophoresis

Marín

García-Núñez

Ruiz

et al. 2013

Applied Physics Letters

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Metal oxide nanowire (NW) photoconductors tend to exhibit high photoconductive gains and long recovery times mainly due to surface effects. In this work, p-type CuO NWs are synthesized by direct oxidation of copper and deposited on n-type ZnO:Al electrodes by dielectrophoresis. The heterostructure is electro-optically characterized showing recovery times in the 10 ls range, mainly limited by the resistance-capacitance product of the equivalent circuit, without signs of persistent effects. The fast response is attributed to short transit times across space charge regions built between CuO and ZnO:Al materials and fast carrier recombination at neutral regions. V C 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4811128] Metal oxides (MOs) are attractive compounds for industrial purposes since high-quality crystal nanowires (NWs) can be obtained by cost-effective methods that do not require expensive vacuum systems or environmentally unfriendly chemical reactants. The high surface-to-volume ratio of such nanostructures leads to the enhancement of the device sensitivity prompting their use as building blocks in low-cost optical, biological, and gas sensors. [1][2][3][4] Regarding light detectors, NWs may help to reduce the operation voltages of high-gain sensors through the proximity of the surface and the subsequent enhancement of the local electric field. In addition, their small dimensions open possibilities for the integration of NWs from different materials or with different structures such as core-shell, p-n junctions, or quantum well superlattices. 5,6 However, the development of NW-based devices has to face issues such as the lack of performance reproducibility or the need for advanced methods to handle and manipulate nanostructures on a high demand basis. Dielectrophoresis (DEP) has long been used in biochemistry to separate biomolecules, but nowadays, it has also been proved to be a costeffective technique to align NWs between metal electrodes. 7,8 The technique is highly scalable and makes possible the precise placement of multiple NWs on Si integrated circuits at room temperature. Thus, ZnO NW devices have been fabricated using this method on Au electrodes. 9 Due to their high conductance and mechanical stability, Al-doped ZnO (AZO) is an alternative material to metals for the preparation of DEP electrodes. Moreover, its visible transparency also enables the alignment of NWs on desired locations of transparent substrates aiming at the development of sensors in transparent electronics.Concerning the performance of NW devices, the understanding of the surface effects is crucial since many of the electrical and optical characteristics are strongly influenced by surface electronic states. On many MO-NW light sensors, these surface effects lead to obtain photoresponse values well beyond those achieved in mesoscopic devices, at the expense of showing long recovery times. 10,11 Unfortunately, these slow transients hinder their practical application in many fields.Recently, p-type cupric oxide (CuO) NWs ha...

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Effect of surface stresses on CuO nanowire growth in the thermal oxidation of copper

Cited by 115 publications

References 40 publications

Leaching of Malachite Ore in Ammonium Sulfate Solutions and Production of Copper Oxide

Leaching of Malachite Ore in Ammonium Sulfate Solutions and Production of Copper Oxide

Formation of urchin-like CuO structure through thermal oxidation and its field-emission lighting application

Fast response ZnO:Al/CuO nanowire/ZnO:Al heterostructure light sensors fabricated by dielectrophoresis

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