Computer Simulation Of The Cross-Sectional Morphology Of Thin Films

Yang, Bing; Walden, Barbara L.; Messier, R.; White, William Β.

doi:10.1117/12.941843

Cited by 18 publications

(3 citation statements)

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“…Typically, as a CTF is grown on a planar substrate mounted on a platform, the tops of the columns together constitute a surface that is almost planar. When the substrate has a slight undulation, possibly because of a dust particle or a manufacturing defect, that undulation, which is highly undesirable for most practical CTF applications in such fields as optics or microelectronics, is manifested at the top surface (4). Consequently, if a CTF were to be deposited on a fingermark, the top surface of the CTF would be expected to reproduce the topological details of the fingermark.…”

mentioning

confidence: 99%

Solid-State Acquisition of Fingermark Topology using Dense Columnar Thin Films

Lakhtakia

Shaler

Martín-Palma

et al. 2011

Journal of Forensic Sciences

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Various vacuum techniques are employed to develop fingermarks on evidentiary items. In this work, a vacuum was used to deposit columnar thin films (CTFs) on untreated, cyanoacrylate-fumed or dusted fingermarks on a limited selection of nonporous surfaces (microscope glass slides and evidence tape). CTF deposition was not attempted on fingermarks deposited on porous surfaces. The fingermarks were placed in a vacuum chamber with the fingermark side facing an evaporating source boat containing either chalcogenide glass or MgF(2). Thermal evaporation of chalcogenide glass or MgF(2) under a 1 μTorr vacuum for 30 min formed dense CTFs on fingermark ridges, capturing the topographical features. The results show that it is possible to capture fingermark topology using CTFs on selected untreated, vacuumed cyanoacrylate-fumed or black powder-dusted nonporous surfaces. Additionally, the results suggested this might be a mechanism to help elucidate the sequence of deposition.

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mentioning

confidence: 99%

Solid-State Acquisition of Fingermark Topology using Dense Columnar Thin Films

Lakhtakia

Shaler

Martín-Palma

et al. 2011

Journal of Forensic Sciences

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“…In contrast, the substrate is held stationary in traditional OAD methods employing thermal evaporation, electron-beam evaporation or sputtering. These traditional methods are able to replicate substrate nonplanarities, although the fidelity of replication begins to diminish as the thinfilm coating grows thicker [18]. As the film thickness is increased, any departure from planarity in the substrate creates a disturbance that increases in lateral extent with increasing thickness, the morphology of a growing thin film being governed by the evolution of power-law cones originating from small nucleation clusters or substrate nonplanarities (such as particles and indentations).…”

Section: Resultsmentioning

confidence: 99%

Replication of fly eyes by the conformal-evaporated-film-by-rotation technique

Martín-Palma¹,

Pantano²,

Lakhtakia³

2008

Nanotechnology

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We replicated a biological template, namely the eye of a fruit fly, at the micro- and nanoscales by implementing the conformal-evaporated-film-by-rotation (CEFR) technique, which allows the replication of even curved biotemplates. Chalcogenide glasses were used for replication due to their infrared optical properties, combined with good chemical and mechanical durability. Microscopy, together with optical characterization in the visible and near-infrared ranges, indicates high-fidelity replication of the original biotemplate. The CEFR technique could be useful for the development of highly efficient, biomimetic optical devices.

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“…It is possible to model columnar growth in a completely mechanistic way -no assumptions about chemistry or crystallography (Yang et al, 1987). The model assumes that growth originates on seeds scattered randomly over the substrate.…”

Section: Columnar Aggregatesmentioning

confidence: 99%

Speleothem microstructure/speleothem ontogeny: a review of Western contributions

White¹

2012

IJS

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Mineral ontogeny is the study of the growth and development of mineral deposits in general and, in the present context, speleothems in particular. Previous researchers, mainly in Russia, have developed a nomenclatural hierarchy based on the forms and habits of individual crystals and the assembly of individual crystals into both monomineralic and polymineralic aggegates (i.e. speleothems). Although investigations of the growth processes of speleothems are sparse, there is a large literature on growth processes of speleothem minerals and related crystals in the geochemical and materials science literature. The purpose of the present paper is to sort through the various concepts of crystal growth and attempt to relate these to observations on speleothems and to the Russian conceptual framework of mineral ontogeny. For calcite, the most common mineral in speleothems, the activation energy for two dimensional nucleation (required for the growth of large single crystals) is almost the same as the activation energy for threedimensional nucleation (which would result in the growth of many small crystals). Calcite growth is highly sensitive to minor impurities that may poison growth in certain crystallographic directions or may poison growth altogether. Extensive recent research using the atomic force microscope (AFM) provides many details of calcite growth including the transition from growth on screw dislocations to growth by two-dimensional nucleation. The deposition of aragonite speleothems requires metastable supersaturation curve and is usually ascribed to the impurities Mg 2+ and Sr 2+ . AFM studies reveal that Mg 2+ poisons calcite growth by blocking deposition sites on dislocations, thus allowing supersaturation to build up past the aragonite solubility curve. Sr 2+ precipitates as a Sr-rich nucleus with the aragonite structure which acts as a template for aragonite growth. The different morphology of gypsum speleothems can be explained by the different growth habit of gypsum. Examples of twinned growth, dendrite growth, and spherulitic growth are common in the crystal growth literature and can be used to interpret the corresponding cave forms. Interpretation of monomineralic aggregate growth follows from individual crystal mechanisms. Interpretation of polymineralic aggregate growth requires knowing the evolving chemistry which in turn requires new methods for the sampling and analysis of microliter or nanoliter quantities of fluid.

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Computer Simulation Of The Cross-Sectional Morphology Of Thin Films

Cited by 18 publications

References 0 publications

Solid-State Acquisition of Fingermark Topology using Dense Columnar Thin Films

Solid-State Acquisition of Fingermark Topology using Dense Columnar Thin Films

Replication of fly eyes by the conformal-evaporated-film-by-rotation technique

Speleothem microstructure/speleothem ontogeny: a review of Western contributions

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