Van der Waals Epitaxial Growth of α-Alumina Nanocrystals on Mica

Steinberg, Suzi; Ducker, William A.; Vigil, Gene; Hyukjin, C.; Frank, Curtis W.; Tseng, Ming-Hung; Clarke, David R.; Israelachvili, Jacob N.

doi:10.1126/science.260.5108.656

Cited by 57 publications

(33 citation statements)

References 21 publications

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“…Using SFA interferometry with the pin-on-disk geometry would require this more stringent alignment, along with preparation of a smooth spherical surface as described elsewhere [19][20][21][22]. In addition, an optically appropriate annulus on the flat disk would be required along the sliding path, which could be opaque and reflecting for reflected beam interferometry [23].…”

Section: Use Of Rotating Disk In Sfamentioning

confidence: 99%

High-Speed Friction Measurements Using a Modified Surface Forces Apparatus

et al. 2011

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Methods of measuring friction forces in the surface forces apparatus (SFA) are presented for sliding velocities from \1 nm/s to [10 m/s. A feed-forward control (FFC) system for the piezoelectric bimorph slider attachment is introduced to allow experiments at velocities up to *4 mm/s. For still higher speeds, a motor-driven rotating mini-disk setup using a pin-on-disk geometry is presented, with modifications to enable sliding velocities in the ranges 1 cm/s-5 m/s and 1-25 m/s. Example data sets demonstrate the applicability of the approach to modeling important tribological systems including hard-disk drives. We find that mechanical system parameters such as the resonant frequencies and mutual alignments of different moving parts become increasingly important in determining the tribological response at sliding velocities above *1 cm/s (for SFA or bench top devices). Smooth or stick-slip sliding-common features of low-speed sliding-become replaced by large-amplitude oscillatory responses that depend on the load and especially the driving speed or rotational/reciprocating frequencies.Detailed recordings and modeling of these complex effects are necessary for fully understanding and controlling frictional behavior at high speeds.

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Section: Use Of Rotating Disk In Sfamentioning

confidence: 99%

High-Speed Friction Measurements Using a Modified Surface Forces Apparatus

et al. 2011

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“…Inorganic overlayers possess a rigidity that inhibits deformation required for achieving commensurism (when a commensurate configuration with the native overlayer is not available), leaving only azimuthal rotation as a route to achieving a minimum interfacial energy. Examples of coincidence in inorganic overlayers include transition metal dichalcogenides (TX 2 ) on mica, [44] metal dihalides on TX 2 , [45] a-alumina nanocrystals on mica, [46] CdSe on Au, [47] Bi 2 O 3 on Au, [48] AgBr on Au, [49] Ag on highly oriented pyrolytic graphite (HOPG), [50] PtCl 6 on Au, [51] simple face-centered cubic (fcc) and body-centered cubic (bcc) systems, [52,53] and others. [54,55] The concept of coincidence actually has its roots in the description of grain boundaries.…”

Section: A Grammar Of Epitaxymentioning

confidence: 99%

Epitaxy and Molecular Organization on Solid Substrates

2001

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The recent emergence of molecular films as candidates for functional electronic materials has prompted numerous investigations of the underlying mechanisms responsible for their structure and formation. This review describes the role of epitaxy in molecular organization on crystalline substrates. A much‐needed grammar of epitaxy is presented that classifies the various modes of epitaxy according to transformation matrices that relate the overlayer lattice to the substrate lattice. The different modes of epitaxy can be organized hierarchically to reflect the balance of overlayer–substrate and molecule–molecule energies. In the case of molecular overlayers, the mismatch of overlayer and substrate symmetries commonly leads to coincident epitaxy in which some of the overlayer lattice points do not reside on substrate lattice points. Analyses of numerous reported epitaxial molecular films reveal that coincidence is quite common even though, based on overlayer–substrate interface energies alone, not as energetically favorable as commensurism. The prevalence of coincidence can be attributed to overlayer elastic constants, associated with molecule–molecule interactions within the overlayer, that are larger than the elastic constants of the overlayer–substrate interface. This condition facilitates prediction of the epitaxial configuration and overlayer structure through simple and comparatively efficient geometric modeling that does not require the input of potential energies, while revealing the role of phase coherence between the overlayer and substrate lattices.

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“…The sapphire is often used as a substrate in the integrated circuits industry, optoelectronic industry and for many scientific applications 1 2 3 4 5 6 7 8 9 10 11 . For film and epitaxy, the substrate surface properties greatly affect the growing quality 2 4 5 6 12 .…”

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confidence: 99%

Atomic Step Formation on Sapphire Surface in Ultra-precision Manufacturing

Wang

Guo

Xie

et al. 2016

Sci Rep

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Surfaces with controlled atomic step structures as substrates are highly relevant to desirable performances of materials grown on them, such as light emitting diode (LED) epitaxial layers, nanotubes and nanoribbons. However, very limited attention has been paid to the step formation in manufacturing process. In the present work, investigations have been conducted into this step formation mechanism on the sapphire c (0001) surface by using both experiments and simulations. The step evolutions at different stages in the polishing process were investigated with atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). The simulation of idealized steps was constructed theoretically on the basis of experimental results. It was found that (1) the subtle atomic structures (e.g., steps with different sawteeth, as well as steps with straight and zigzag edges), (2) the periodicity and (3) the degree of order of the steps were all dependent on surface composition and miscut direction (step edge direction). A comparison between experimental results and idealized step models of different surface compositions has been made. It has been found that the structure on the polished surface was in accordance with some surface compositions (the model of single-atom steps: Al steps or O steps).

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Van der Waals Epitaxial Growth of α-Alumina Nanocrystals on Mica

Cited by 57 publications

References 21 publications

High-Speed Friction Measurements Using a Modified Surface Forces Apparatus

High-Speed Friction Measurements Using a Modified Surface Forces Apparatus

Epitaxy and Molecular Organization on Solid Substrates

Atomic Step Formation on Sapphire Surface in Ultra-precision Manufacturing

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