Steps and the structure of the (0001) α-alumina surface

Heffelfinger, J. R.; Bench, M. W.; Carter, C. Barry

doi:10.1016/s0039-6028(96)01123-5

Cited by 101 publications

(80 citation statements)

References 22 publications

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“…After annealing at 1450 • C for 24 h, the surface was measured with atomic force microscopy (AFM) in tapping mode and showed the typical quasiperiodic pattern of facets and terraces previously reported. 21 Axes are defined with respect to the vicinal substrate. The x and y axes lie in the optical plane, parallel and perpendicular to the steps, respectively, with the z axis normal to the surface plane.…”

Section: Methodsmentioning

confidence: 99%

Probing the out-of-plane optical response of plasmonic nanostructures using spectroscopic ellipsometry

Verre¹,

Fleischer²,

Smith³

et al. 2011

Phys. Rev. B

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A simplified approach to investigate the out-of-plane response of plasmonic nanostructures using spectroscopic ellipsometry (SE) is presented. One-dimensional self-assembled arrays of Ag nanoparticles (NP's) were grown on stepped Al 2 O 3 (0001), in ultrahigh vacuum, using deposition at a glancing angle. The SE response was measured with the plane of incidence aligned along, and across, the surface steps. From the raw data, an anisotropic surface excess function (ASEF) can be extracted, whose properties depend only on the dielectric function of the NP layer. Three resonances are clearly seen in the ASEF: two in-plane resonances, which correspond to the resonances measured using normal incidence reflection anisotropy spectroscopy, and the out-of-plane resonance. A dipole model is used to simulate the optical response of the NP layer, where the presence of the out-of-plane resonance provides an important additional constraint in developing the model.

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Section: Methodsmentioning

confidence: 99%

Probing the out-of-plane optical response of plasmonic nanostructures using spectroscopic ellipsometry

Verre¹,

Fleischer²,

Smith³

et al. 2011

Phys. Rev. B

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“…These templates have recently attracted additional interest as they offer the possibility of reconstructing their surfaces into a hill and valley structure [9]. It was demonstrated that annealing of the (0001) surface can produce periodic step-and-terrace arrangements with a step height h ∼ 1.2 nm [10].…”

Section: Introductionmentioning

confidence: 99%

“…It was demonstrated that annealing of the (0001) surface can produce periodic step-and-terrace arrangements with a step height h ∼ 1.2 nm [10]. The step rearrangements of c-plane α-Al 2 O 3 have been previously investigated as a function of parameters such as annealing temperature [10,11,12,13], time [9,13,11,14], atmospheric environment [12], pressure [15], off-cut angle [13,16] and orientation [13]. If the surface is off-cut along the [1210] direction, the resulting vicinal surface before annealing appears covered by steps running along the [1010] direction.…”

Section: Introductionmentioning

confidence: 99%

Equilibrium faceting formation in vicinal Al2O3 (0001) surface caused by annealing

et al. 2012

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We report on a heat-induced transformation of the surface of α-alumina (0001) crystals which have a off-cut in the [1210] direction. Annealing the crystal causes the surface to transform into a regular array of (0001) and (1216) facets. The resultant faceted morphology represents the equilibrium state of the system. It is demonstrated that the average terrace periodicity is determined by the annealing temperature. Possible causes for the surface rearrangement are also discussed. The method could be used for producing templates with controlled periodicity for growth of nanostructure arrays.

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“…These observations suggest that the { } 1210 faces are unstable, i.e., not a component of the Wulff shape, and thereby unstable to breakdown into a "hill-and-valley" structure, as originally described by Herring [21]. These observations have a parallel in undoped sapphire, where experimental evidence shows that { } 1210 -type surfaces are stable and develop ledges that increase in height with anneal time, but the orthogonal { } 1010 surfaces break down into a series of inclined facets via a nucleation and growth process [19,[22][23][24].…”

Section: Facetting Behaviormentioning

confidence: 58%

High‐Temperature Morphological Evolution of Lithographically Introduced Cavities in Silicon Carbide

Narushima

Glaeser

2001

Journal of the American Ceramic Society

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Internal cavities of controlled geometry and crystallography were introduced in 6H silicon carbide single crystals by combining lithographic methods, ion beam etching, and solid-state diffusion bonding. The morphological evolution of these internal cavities (negative crystals) in response to anneals of up to 128 h duration at 1900°C was examined using optical microscopy. Surface energy anisotropy and facetting have a strong influence on both the geometric and kinetic characteristics of evolution. Decomposition of { } 1210 cavity edges into { } 101 x facets was observed after 16 h anneals, indicating that { } 1210 faces are not components of the Wulff shape. The shape evolution kinetics of penny-shaped cavities were also investigated. Experimentally observed evolution rates decreased much more rapidly with those predicted by a model in which surface diffusion is assumed to be ratelimiting. This suggests that the development of facets, and the associated loss of ledges and terraces during the initial stages of evolution results in an evolution process limited by the nucleation rate of attachment/detachment sites (ledges) on the facets.

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Steps and the structure of the (0001) α-alumina surface

Cited by 101 publications

References 22 publications

Probing the out-of-plane optical response of plasmonic nanostructures using spectroscopic ellipsometry

Probing the out-of-plane optical response of plasmonic nanostructures using spectroscopic ellipsometry

Equilibrium faceting formation in vicinal Al2O3 (0001) surface caused by annealing

High‐Temperature Morphological Evolution of Lithographically Introduced Cavities in Silicon Carbide

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