TEM investigation of interfaces during cuprous island growth

Zhou, Guangwen

doi:10.1016/j.actamat.2009.06.005

Cited by 35 publications

(22 citation statements)

References 50 publications

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“…We note that the Cu/Cu 2 O interfacial energy is the sum of misfit strain energy and chemical interaction energy of the interfacial region 27 . The lattice misfit between Cu and Cu 2 O is around 15%, implying a large interfacial strain energy, even though the strained structure can be relaxed to some extent by forming misfit dislocations 28 . The chemical interaction energy usually depends on the composition of contacting materials, but it is also modulated by nanostructured interfaces 29 .…”

Section: Resultsmentioning

confidence: 99%

Suppression of interdiffusion-induced voiding in oxidation of copper nanowires with twin-modified surface

et al. 2018

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Cavitation and hollow structures can be introduced in nanomaterials via the Kirkendall effect in an alloying or reaction system. By introducing dense nanoscale twins into copper nanowires (CuNWs), we change the surface structure and prohibit void formation in oxidation of the nanowires. The nanotwinned CuNW exhibits faceted surfaces of very few atomic steps as well as a very low vacancy generation rate at copper/oxide interfaces. Together they lower the oxidation rate and eliminate void formation at the copper/oxide interface. We propose that the slow reaction rate together with the highly effective vacancy absorption at interfaces leads to a lattice shift in the oxidation reaction. Our findings suggest that the nanoscale Kirkendall effect can be manipulated by controlling the internal and surface crystal defects of nanomaterials.

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Section: Resultsmentioning

confidence: 99%

Suppression of interdiffusion-induced voiding in oxidation of copper nanowires with twin-modified surface

et al. 2018

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“…Copper oxidation on this surface proceeds, for low oxygen partial pressures (P ∼ 10 −4 Torr), through the formation of islands which are epitaxial with the surface, i.e. Cu 2 O(100) || Cu(100) 113,115,231,233-236 and have 6 × 7 lattice misfit configuration 225,237 . These islands grow and coalesce with further oxygen deposition.…”

Section: Oxide Nano-islands: Cu(100)mentioning

confidence: 99%

Atomistic details of oxide surfaces and surface oxidation: the example of copper and its oxides

Gattinoni

Michaelides

2015

Surface Science Reports

279

258

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The oxidation and corrosion of metals are fundamental problems in materials science and technology that have been studied using a large variety of experimental and computational techniques. Here we review some of the recent studies that have led to significant advances in our atomic-level understanding of copper oxide, one of the most studied and better understood metal oxides. We show that a good atomistic understanding of the physical characteristics of cuprous (Cu 2 O) and cupric (CuO) oxide and of some key processes of their formation has been obtained. Indeed, the growth of the oxide has been proven to be epitaxial with the surface and to proceed, in most cases, through the formation of oxide nano-islands which, with continuous oxygen exposure, grow and eventually coalesce. We also show how electronic structure calculations have become increasingly useful in helping to characterise the structures and energetics of various Cu oxide surfaces. However a number of challenges remain. For example, it is not clear under which conditions the oxidation of copper in air at room temperature (known as native oxidation) leads to the formation of a cuprous oxide film only, or also of a cupric overlayer. Moreover, the atomistic details of the nucleation of the oxide islands are still unknown. We close our review with a perspective on future work and discuss how recent advances in experimental techniques, bringing greater temporal and spatial resolution, along with improvements in the accuracy, realism and timescales achievable with computational approaches make it possible for these questions to be answered in the near future.

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“…Those values are also lower than that observed values in the TEM image (Figure 8b). On the other way, considering the interplanar spacings d 1 and d 2 of two overlapping crystals, the d spacing of parallel moire’ fringes will be increased [51]. Even though the Cu will be mixed in the Ge 0.2 Se 0.8 in the filament region, however, the d spacing of Cu will be also increased, which may be overlapping of different Cu nanocrystal fringes or Cu and GeSe nanocrystal fringes.…”

Section: Resultsmentioning

confidence: 99%

Enhanced nanoscale resistive switching memory characteristics and switching mechanism using high-Ge-content Ge0.5Se0.5 solid electrolyte

et al. 2012

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We demonstrate enhanced repeatable nanoscale bipolar resistive switching memory characteristics in Al/Cu/Ge0.5Se0.5/W, as compared with Al/Cu/Ge0.2Se0.8/W structures, including stable AC endurance (>105 cycles), larger average SET voltage (approximately 0.6 V), excellent data retention (>105 s) at 85°C, and a high resistance ratio (>104) with a current compliance of 8 μA and a small operation voltage of ±1.5 V. A small device size of 150 × 150 nm2 and a Cu nanofilament with a small diameter of 30 nm are both observed by high-resolution transmission electron microscope in the SET state. The GexSe1 − x solid electrolyte compositions are confirmed by both energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The switching mechanism relies on the smaller barrier heights for holes rather than for electrons; the positively charged Cuz+ ions (i.e., holes) migrate through the defects in the GexSe1 − x solid electrolytes during SET/RESET operations. Hence, the Cu nanofilament starts to grow at the Ge0.5Se0.5/W interface, and starts to dissolve at the Cu/Ge0.5Se0.5 interface, as illustrated in the energy band diagrams. Owing to both the higher barrier for hole injection at the Cu/Ge0.5Se0.5 interface than at the Cu/Ge0.2Se0.8 interface and greater thermal stability, the resistive switching memory characteristics of the Al/Cu/Ge0.5Se0.5/W are improved relative to the Al/Cu/Ge0.2Se0.8/W devices. The Al/Cu/Ge0.5Se0.5/W memory device can also be operated with a low current compliance of 1 nA, and hence, a low SET/RESET power of 0.61 nW/6.4 pW is achieved. In addition, a large memory size of 1,300 Pbit/in2 is achieved with a small nanofilament diameter of 0.25 Å for a small current compliance of 1 nA.

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TEM investigation of interfaces during cuprous island growth

Cited by 35 publications

References 50 publications

Suppression of interdiffusion-induced voiding in oxidation of copper nanowires with twin-modified surface

Suppression of interdiffusion-induced voiding in oxidation of copper nanowires with twin-modified surface

Atomistic details of oxide surfaces and surface oxidation: the example of copper and its oxides

Enhanced nanoscale resistive switching memory characteristics and switching mechanism using high-Ge-content Ge0.5Se0.5 solid electrolyte

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