Real-time coarsening dynamics of Ge∕Si(100) nanostructures

McKay, Michael; Shumway, John; Drucker, Jeffery

doi:10.1063/1.2191574

Cited by 16 publications

(18 citation statements)

References 13 publications

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“…Some examples for complex metal-containing thin film systems are as follows: Pb nanoclusters on an MgO(100) oxide surface where coarsening kinetics displays nanoscale corrections; 40 formation and coarsening of partial and/or complete Ag bilayer islands on NiAl (110); 41 anomalous rapid coarsening in the Pb/ Si(111) system due to quantum size effects. 42 In addition, there are a substantial number of studies of coarsening for Ge/Si (111) semiconductor quantum dot systems, [43][44][45][46] which include assessment of anomalous behavior due to quantum dot shape transitions. 47 The second phenomenon discussed in this article is the effect of trace amounts of chemical additives on coarsening in metal homoepitaxial systems.…”

Section: Introductionmentioning

confidence: 99%

Coarsening of Two-Dimensional Nanoclusters on Metal Surfaces

et al. 2009

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We describe experimental observations and theoretical analysis of the coarsening of distributions of twodimensional nanoclusters, either adatom islands or vacancy pits, on metal surfaces. A detailed analyses is provided for Ag(111) and Ag(100) surfaces, although we also discuss corresponding behavior for Cu(111) and Cu(100) surfaces. The dominant kinetic pathway for coarsening can be either Ostwald ripening (OR), i.e., growth of larger clusters at the expense of smaller ones, or Smoluchowski ripening (SR), i.e., diffusion and coalescence of clusters. First, for pristine additive-free surfaces, we elucidate the factors which control the dominant pathway. OR kinetics generally follows the predictions of mesoscale continuum theories. SR kinetics is controlled by the size-dependence of cluster diffusion. However, this size-dependence, together with that of nanostructure shape relaxation upon coalescence, often deviates from mesoscale predictions as a direct consequence of the nanoscale dimension of the clusters. Second, we describe examples for the above systems where trace amounts of a chemical additive lead to dramatic enhancement of coarsening. We focus on the scenario where "facile reaction" of metal and additive atoms leads to the formation of mobile additivemetal complexes which can efficiently transport metal across the surface, i.e., additive-enhanced OR. A suitable reaction-diffusion equation formulation is developed to describe this behavior. ReceiVed: July 19, 2008; ReVised Manuscript ReceiVed: December 25, 2008 We describe experimental observations and theoretical analysis of the coarsening of distributions of twodimensional nanoclusters, either adatom islands or vacancy pits, on metal surfaces. A detailed analyses is provided for Ag(111) and Ag(100) surfaces, although we also discuss corresponding behavior for Cu (111) and Cu(100) surfaces. The dominant kinetic pathway for coarsening can be either Ostwald ripening (OR), i.e., growth of larger clusters at the expense of smaller ones, or Smoluchowski ripening (SR), i.e., diffusion and coalescence of clusters. First, for pristine additive-free surfaces, we elucidate the factors which control the dominant pathway. OR kinetics generally follows the predictions of mesoscale continuum theories. SR kinetics is controlled by the size-dependence of cluster diffusion. However, this size-dependence, together with that of nanostructure shape relaxation upon coalescence, often deviates from mesoscale predictions as a direct consequence of the nanoscale dimension of the clusters. Second, we describe examples for the above systems where trace amounts of a chemical additive lead to dramatic enhancement of coarsening. We focus on the scenario where "facile reaction" of metal and additive atoms leads to the formation of mobile additivemetal complexes which can efficiently transport metal across the surface, i.e., additive-enhanced OR. A suitable reaction-diffusion equation formulation is developed to describe this behavior.

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Section: Introductionmentioning

confidence: 99%

Coarsening of Two-Dimensional Nanoclusters on Metal Surfaces

et al. 2009

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“…Since the (Si)Ge systems contain a Ge surface, whereas the (Ge)Si systems contain a surface of Si atoms, this result may be a simple consequence of the lower surface energy of Ge compared with that of Si (see, e.g., [21]). …”

Section: Resultsmentioning

confidence: 99%

Structural and electronic properties ofSi∕Genanoparticles

Asaduzzaman

Springborg

2006

Phys. Rev. B

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Results of a theoretical study of the electronic properties of (Si)Ge and (Ge)Si core/shell nanoparticles, homogeneous SiGe clusters, and Ge|Si clusters with an interphase separating the Si and Ge atoms are presented. In general, (Si)Ge particles are more stable than (Ge)Si ones, and SiGe systems are more stable than Ge|Si ones. It is found that the frontier orbitals, that dictate the optical properties, are localized to the surface, meaning that saturating dangling bonds on the surface with ligands may influence the optical properties significantly. In the central parts we identify a weak tendency for the Si atoms to accept electrons, whereas Ge atoms donate electrons.

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“…These clusters act as sinks for diffusing Ge atoms, which leads to their ripening at the cost of the surrounding wires. 40 For pure Ge we found after t a = 16 h a denuded zone around each pillow that contains a few dome islands, but no wires at all (Fig. 5(b)).…”

confidence: 97%

“…5(a)) and density the Ge clusters described in Ref. 40. These clusters act as sinks for diffusing Ge atoms, which leads to their ripening at the cost of the surrounding wires.…”

confidence: 99%

Influence of composition and substrate miscut on the evolution of {105}-terminated in-plane Si1−xGex quantum wires on Si(001)

et al. 2014

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Isolated in-plane wires on Si(001) are promising nanostructures for quantum transport applications. They can be fabricated in a catalyst-free process by thermal annealing of self-organized Si1−xGex hut clusters. Here, we report on the influence of composition and small substrate miscuts on the unilateral wire growth during annealing at 570 °C. The addition of up to 20% of Si mainly affects the growth kinetics in the presence of energetically favorable sinks for diffusing Ge atoms, but does not significantly change the wire base width. For the investigated substrate miscuts of <0.12°, we find geometry-induced wire tapering, but no strong influence on the wire lengths. Miscuts <0.02° lead to almost perfect quantum wires terminated by virtually step-free {105} and {001} facets over lengths of several 100 nm. Generally, the investigated Si1−xGex wires are metastable: Annealing at ≥600 °C under otherwise identical conditions leads to the well-known coexistence of Si1−xGex pyramids and domes.

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Real-time coarsening dynamics of Ge∕Si(100) nanostructures

Cited by 16 publications

References 13 publications

Coarsening of Two-Dimensional Nanoclusters on Metal Surfaces

Coarsening of Two-Dimensional Nanoclusters on Metal Surfaces

Structural and electronic properties ofSi∕Genanoparticles

Influence of composition and substrate miscut on the evolution of {105}-terminated in-plane Si1−xGex quantum wires on Si(001)

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