Effect of misfit dislocation on surface diffusion

Aminpour, Maral; Trushin, Oleg; Rahman, Talat S.

doi:10.1103/physrevb.84.035455

Cited by 9 publications

(3 citation statements)

References 22 publications

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“…As the surface terminating TDs exert a local strain field, they alter the step-edge potential profile, and thereby can pin surface step edges, leading to roughening. The impact of surface terminating dislocations on adatom diffusion, and step advance has been studied both theoretically and experimentally in a number of materials. − We empirically test this mechanism as a possible explanation for the roughening transition in ZnS/GaP by correlating the AFM morphology measurements with the ECCI-based TD density measurements. Besides RMS roughness, ( R q ), image processing of the AFM images allows measurement of the average diameter ( d i ), height ( R i ), and density of islands with height >1 ML (ρ i ), which are most pronounced in the 50-nm-thick sample (Figure (c)).…”

Section: Resultsmentioning

confidence: 99%

Log-Normal Glide and the Formation of Misfit Dislocation Networks in Heteroepitaxial ZnS on GaP

Fonseca Montenegro,

Baan,

Ghazisaeidi

et al. 2024

Crystal Growth & Design

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Scanning electron microscopy (SEM)-based electron channeling contrast imaging (ECCI) is used to observe and quantify misfit dislocation (MD) networks formed at the heteroepitaxial interface between ZnS and GaP grown by molecular beam epitaxy (MBE). Below a critical thickness of 15−20 nm, no MDs are observed. However, crystallographic features with strong dipole contrast, consistent with unexpanded dislocation half-loops, are observed prior to the formation of visible interfacial MD segments and any notable strain relaxation. At higher film thicknesses (20 to 50 nm), interfacial MD lengths increase anisotropically in the two orthogonal in-plane ⟨110⟩ line directions, threading dislocation (TD) density increases, and a roughening transition is observed from atomically smooth twodimensional (2D) to a multistepped three-dimensional (3D) morphology, providing evidence for step edge pinning via surface terminating dislocations. The ZnS strain relaxation, calculated from the total MD content observed via ECCI, matches the average strain relaxation measured by high-resolution X-ray diffraction (HRXRD). The MD lengths are found to follow a log-normal distribution, indicating that the combined MD nucleation and TD glide processes must have a normal distribution of activation energies. The estimated TD glide velocity (v g ) along [110] is almost twice that along [110], but in both directions shows a maximum as a function of film thickness, indicating an initial burst of plasticity followed by dislocation pinning.

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Section: Resultsmentioning

confidence: 99%

Log-Normal Glide and the Formation of Misfit Dislocation Networks in Heteroepitaxial ZnS on GaP

Fonseca Montenegro,

Baan,

Ghazisaeidi

et al. 2024

Crystal Growth & Design

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“…Interphase boundaries in nanostructured composites (nanocomposites) play a significant role in the formation of mechanical, physical, and chemical properties of these materials and, therefore, are the subject of intensive scientific research (see, e.g., [1][2][3][4][5][6][7][8][9][10][11][12]). As a rule, such boundaries are characterized by a dilatational misfit caused by a mismatch between the lattice parameters of different phases.…”

Section: Introductionmentioning

confidence: 99%

Dislocation emission from interphase boundaries in deformed nanocomposites

Bobylev

Ovid’ko

2016

Phys. Solid State

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A theoretical model for emission of lattice dislocations from small-angle interphase boundaries characterized by both orientational and dilatational misfit in deformed nanocomposites is proposed. With allowance for the free surface of the material, the forces acting upon the dislocation structures of the interphase boundaries are calculated, through which the dependences of the critical shear stress for dislocation emission on different parameters of the boundary are found. It is shown that the influence of dilatational misfit and proximity of the interphase boundary to the free surface on dislocation emission is insignificant. It is established that the ability of interphase boundaries to emit dislocations is not uniform: emission of certain dislocations is facilitated as compared to ordinary small-angle grain boundaries, while emission of other dislocations may be inhibited.

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“…[28][29][30][31] The interface interaction between NPs and carriers can be perceived as the dominant aspect of these aggregation and dispersion procedures. [32][33][34][35] Therefore, it is of great significance to investigate the evolutionary process of NPs on its support, which is meaningful for the preparation and practical application of SACs.…”

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confidence: 99%

Nanoscale Self‐Wetting Driven Monatomization of Ag Nanoparticle for Excellent Photocatalytic Hydrogen Evolution

Yan

Yang

2022

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Metal nanoparticles (NPs) with <10 nm have demonstrated many novel applications including surprisingly low melting point, astonishing liquidlike pseudoelasticity, and outstanding hydrogen evolution performance. Here, a nanoscale self-wetting driven monatomization of Ag NPs with <5 nm on carbon nitride (CN) to fabricate Ag single-atom catalyst (Ag 1 /CN SAC) is demonstrated, and a thermodynamic approach to elucidate Ag NPs decomposing into single atoms is established. Dynamic dispersion process of Ag NPs into atoms on CN is recorded using in situ AC-HADDF-TEM techniques. Density functional theory calculations and molecular dynamics simulations suggest that the spontaneous dispersion origins from the nanoscale self-wetting effect in thermodynamics. In atomic scale, the driving force of self-wetting derived from the balance between cohesive energy of Ag NPs and excess energy of Ag atoms in CN vacations. The fabricated Ag 1 /CN SAC proved a higher efficiency for photocatalytic hydrogen evolution activity (3690 μmmol g −1 h −1 ) than Pt nanoparticles on CN (3192 μmmol g −1 h −1 ). This spontaneous monatomization resulting from the interaction between metal NPs and substrate provides a simple method to prepare SACs with a high active photocatalytic hydrogen evolution.

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Effect of misfit dislocation on surface diffusion

Cited by 9 publications

References 22 publications

Log-Normal Glide and the Formation of Misfit Dislocation Networks in Heteroepitaxial ZnS on GaP

Log-Normal Glide and the Formation of Misfit Dislocation Networks in Heteroepitaxial ZnS on GaP

Dislocation emission from interphase boundaries in deformed nanocomposites

Nanoscale Self‐Wetting Driven Monatomization of Ag Nanoparticle for Excellent Photocatalytic Hydrogen Evolution

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