Step-Edge Directed Metal Oxidation

Zhu, Qing; Saidi, Wissam A.; Yang, Judith C.

doi:10.1021/acs.jpclett.6b00895

Cited by 37 publications

(68 citation statements)

References 43 publications

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“…Nucleation events generally led to a growth rate decrease in previously grown layers, indicating that Cu and O attachment to the nucleating new layer is preferred over attachment to previous layers. This is likely caused by the Ehrlich–Schwöbel effect, in which downward diffusion across a surface step is prohibited due to an extra energy barrier 42 – 44 . Concerted diffusion events generally showed sudden decreases in the growth rates of new layers and increases in those of previous layers.…”

Section: Resultsmentioning

confidence: 99%

Unusual layer-by-layer growth of epitaxial oxide islands during Cu oxidation

Curnan

Gresh-Sill

et al. 2021

Nat Commun

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Elucidating metal oxide growth mechanisms is essential for precisely designing and fabricating nanostructured oxides with broad applications in energy and electronics. However, current epitaxial oxide growth methods are based on macroscopic empirical knowledge, lacking fundamental guidance at the nanoscale. Using correlated in situ environmental transmission electron microscopy, statistically-validated quantitative analysis, and density functional theory calculations, we show epitaxial Cu2O nano-island growth on Cu is layer-by-layer along Cu2O(110) planes, regardless of substrate orientation, contradicting classical models that predict multi-layer growth parallel to substrate surfaces. Growth kinetics show cubic relationships with time, indicating individual oxide monolayers follow Frank-van der Merwe growth whereas oxide islands follow Stranski-Krastanov growth. Cu sources for island growth transition from step edges to bulk substrates during oxidation, contrasting with classical corrosion theories which assume subsurface sources predominate. Our results resolve alternative epitaxial island growth mechanisms, improving the understanding of oxidation dynamics critical for advanced manufacturing at the nanoscale.

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Section: Resultsmentioning

confidence: 99%

Unusual layer-by-layer growth of epitaxial oxide islands during Cu oxidation

Curnan

Gresh-Sill

et al. 2021

Nat Commun

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“…III B) because the transition states have a lower number of bonds than the initial state. 68 In the cases of the (110) and (211) surfaces of Ir, Pt, and Au, the relativistic effects present in these heavy atoms are likely influencing 69,70 the bonding with sulfur. Further detailed studies are required to better understand the adoption of sulfur on the (110) and (211) surfaces of Ir, Pt, and Au.…”

Section: A Energetic and Geometric Properties Of Sulfur Adsorbed On mentioning

confidence: 99%

Adsorption and diffusion of sulfur on the (111), (100), (110), and (211) surfaces of FCC metals: Density functional theory calculations

Rodríguez

Santana

2018

The Journal of Chemical Physics

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We have studied the adsorption and diffusion of sulfur at the low-coverage regime of 0.25 ML on the (111), (100), (110), and (211) surfaces of Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au using density functional theory calculations. Sulfur adsorbed preferentially on threefold or four-fold high-coordination sites over most of the studied surfaces. On the Ir(110), Pt(110), and Au(110) surfaces, sulfur is more stable on the twofold sites. Calculations of the minimum energy diffusion pathway show that the energy barrier for the surface diffusion of sulfur depends on the orientation and nature of the metal surfaces. On the (100), sulfur shows the highest diffusion energy, ranging from 0.47 eV in Au(100) to 1.22 eV in Pd(100). In the (110) surface, the diffusion of sulfur is along the channel for Ni, Cu, Rh, Pd, and Ag, and across the channel for Ir, Pt, and Au. In the case of the (211) surfaces, the diffusion is preferentially along the terrace or step-edge sites. Our work provides data for the adsorption of sulfur on many surfaces not previously reported. The present work is a reference point for future computational studies of sulfur and sulfur-containing molecules absorbed on face center cubic metal surfaces.

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“…Due to the fact that the plasticizer is incorporated into the amorphous phase of the polymer matrix, the agent remains independently without attachment to the primary polymer chain . Both ionic conductivity and interfacial polarization of polymer with a high plasticizer content may take less time to complete polarization on the grounds of its larger amorphous domain and superior charge mobility . Note that with a dielectric loss at 1 kHz (Figure b, small box at top right), the loss tan δ increased along with the increasing plasticizer fraction—indicating that the loss of energy mostly depends on the defect sector of the blended polymer and ionic conduction at the low frequency range, i.e., DC breakdown strength.…”

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confidence: 99%

Advanced Plasticized Electroactive Polymers Actuators for Active Optical Applications: Live Mirror

et al. 2020

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The flexibility and semicrystalline structure of electroactive polymers (EAPs) allows a variety of electroactivity developments. The EAPs have been attractive in many sensor-actuator technology fields, especially for electromechanical response [1] in piezoelectric, electrostrictive, and ferroelectric materials. We characterize the response of these polymers to an external electric field with their 1) electrical properties (permittivity, dielectric relaxation, and electrical breakdown) and 2) mechanical properties (Young's modulus). [2] Both characteristics ultimately affect their electromechanical effectiveness. Customized and optimized EAPs have many applications such as rechargeable lithium-ion batteries, [3] enhancing cardiac regeneration, [4] haptic feedback, [5] and tactile sensors. [6] The development of different methods to achieve an excellent actuation response of EAPs was investigated in the polymer/ composite, [7] blended polymer, [8] and structural design [9,10] to improve intrinsic properties. Xia et al. [11] introduced a novel relaxor ferroelectric polymer, leading to the future improvement of EAPs for a broader range of electronic applications. Terpolymers P(VDF-TrFE-CFE/CTFE) presenting the combination of the ferroelectric-paraelectric phase yield a high dielectric constant (ϵ r % 70) and large electromechanical reaction. However, the main drawback of these polymers has been their high electric field requirement (E > 100 V μm À1 ) [12] to reach sufficient strain. Hence, the introduction of the terpolymer/composite including an effective fabrication processing/assembly has been investigated to enhance electromechanical effectiveness. [12,13] This motivates the investigation of advanced terpolymer composites by simply adding the plasticizer agent into the terpolymer matrix. The plasticizer molecule leads to the increased molecular mobility of the polymer chains, resulting in an increasing dielectric permittivity and a decrease in the Young's modulus of the material. The charge trapping at the boundaries of the heterogeneous morphology tends to induce large Maxwell-Wagner-Sillars (MWS) polarization effects. Such an adaptation technique is able to exploit electromechanical coupling through areas of functional sensor-actuator fabrication technology. [13] During the last 10 years, EAPs have been used in several actuator applications, such as artificial muscles, [14] micropumps, [15,16] and smart steerable guidelines. [17] As a result of their flexible and excellent electromechanical properties, EAPs have become attractive soft-actuator candidates in electronic devices. Furthermore, the free-formable attribute of EAPs presents the possibility to carry out numerous different designs. Considering the manufacturing process of piezoelectric and ferroelectric materials for

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Step-Edge Directed Metal Oxidation

Cited by 37 publications

References 43 publications

Unusual layer-by-layer growth of epitaxial oxide islands during Cu oxidation

Unusual layer-by-layer growth of epitaxial oxide islands during Cu oxidation

Adsorption and diffusion of sulfur on the (111), (100), (110), and (211) surfaces of FCC metals: Density functional theory calculations

Advanced Plasticized Electroactive Polymers Actuators for Active Optical Applications: Live Mirror

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