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Showing 1 to 20 of 105 for “"surface diffusion"”.
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Studies of Surface Diffusion
Several different topics, all concerned with surface diffusion are considered. First, the relationship between the diffusion coefficient D and the jump rate (GAMMA) is examined. It is shown that in analogy to alloy diffusion, the diffusivity is given by
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New understandings of surface diffusion
Surface diffusion is of fundamental importance in a variety of industrial kinetic processes, including surface reactions, crystal growth and sintering. However, surface diffusion parameters are rarely used to model industrial processes, resulting from three deficiencies in the literature. First, of …
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Surface Diffusion Kinetics on Amorphous Silicon
In addition, the parameters for self-diffusion on amorphous silicon at processing temperatures (above 635°C) are determined by analyzing our own series of HSG growth experiments using chemical vapor deposition. The results of this study are compared to HSG growth data obtained from MBE growth …
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Surface diffusion by an atomic exchange mechanism
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-13T18:48:35Z No. of bitstreams: 1 1982_wrigley.pdf: 4094675 bytes, checksum: 42d1a17ef62772278d526032ec986f49 (MD5)
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Extraordinary Temperature Amplification in Ion-Stimulated Surface Diffusion
… noble gas atoms impacting semiconductor surfaces revealed a new, unexpectedly strong tradeoff between the energy threshold for point defect formation and substrate temperature. Experimental measurements of Ge and In surface diffusion on Si(111) by optical second harmonic microscopy (SHM) …
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Desorption and Surface Diffusion: Nitrogen on Tungsten (110)
Made available in DSpace on 2014-12-14T16:00:35Z (GMT). No. of bitstreams: 1 7804116.pdf: 4792915 bytes, checksum: ba5e3c05ed584b197539c4094b36dc5a (MD5) Previous issue date: 1977
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Long jumps in surface diffusion on tungsten(211)
The length of the jumps executed by atoms during diffusion is important for understanding atomic transport in crystal growth. Molecular dynamics simulations suggest that atomic jumps longer than a nearest-neighbor spacing should contribute at elevated temperatures. Attempts have been made in the …
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Sintering mechanisms and surface diffusion for aluminum oxide
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1982.
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Electrochemical and NMR Studies of Fuel Cell Catalysts and Carbon Monoxide Surface Diffusion
Surface diffusion of CO adsorbed on Pt nanoparticle catalysts was measured at the solid/liquid interface at and near room temperature, 253 K--293K, by using electrochemical nuclear magnetic resonance (EC-NMR) spectroscopy and a spin labeling pulse sequence. 2H NMR data indicate that the electrolyte …
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Coexistence of surface diffusion mechanisms: jump and exchange for W on W(100)
The thermally-activated coexistence of two diffusion mechanisms, adatom jump and exchange, is a phenomenon that has important potential application in fabrication of quantum dot based devices. If one can initiate the occurrence of a particular diffusion mechanism by changing the temperature, then …
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Surface diffusion processes critical to metallic film nucleation and growth: An atomic view
… simulations have been performed to study diffusion processes critical to nucleation and growth of metallic thin films. Diffusion behavior of (1) single adatoms on a flat surface, (2) single adatoms near and at steps on a vicinal surface, and (3) small adatom cluster migration on terraces …
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Phase behavior of dipolar fluids and ion-dipole mixtures, and surface diffusion of adsorbed polymers
… the last part of this dissertation discusses the diffusion behavior of adsorbed polymers over the full concentration range. In Chapter 2, I study the phase behavior of dipolar fluids by means of Monte Carlo simulations. My goal in this chapter is to examine the possibility of phase separation in a …
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Development of stable operator splitting numerical algorithms for phase-field modeling and surface diffusion applications
… In addition, dewetting of gold films due to surface diffusion was modeled to present the extendability and efficiency of the spectral methods derived. The simulations developed are relevant to many real systems and are relatively light in computational load because they take large time steps …
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Validating surface evolution modeling on high temperature selective emitters : an investigation of the thermal stability of nano-scale surface structures for thermophotovoltaic systems
… over tine. One of the main contributors to surface evolution is surface diffusion. This investigation tested surface diffusion based simulation modeling, comparing computational results with experimental findings for high temperature annealed silicon, a cost effective material for testing …
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The effects of capillarity on photonic crystal selective emitters
… of processes, with one of the most notable being surface evolution by capillary forces. By comprehensively simulating the morphological and optical effects of this phenomenon, in the form of surface diffusion, vapor transport, and grain boundary grooving, this thesis seeks to understand its …
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Diffusion of Prodan on Self -Assembled Monolayers and Grafted Polymer Layers
Two grafted polymer layers were synthesized, for diffusion studies, with surface-initiated polymerization (SIP). The results suggest that there is very little bulk translational diffusion in first layer, poly (N-isopropylacrylamide) (PNIPAM). Rather, fluorescence recovery is thought to be due to …
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Diffusional Phenomena in Microelectronics Processing
For surface diffusion, second ham-ionic microscopy has been utilized to quantify the Arrhenius parameters for diffusion of germanium on silicon at high temperatures. Molecular dynamics simulations provide insight on a picosecond timescale into the complex nature of the mass transfer diffusive …
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Continuum supersonic gas jet enhanced focused electron beam induced deposition
… the precursor injection rate, enhancing surface diffusion, and increasing as-deposited deposition purity. These enhancements are carefully investigated by experiment, theory, and computational simulations and models. Use of argon as a carrier gas in the continuum flow regime is applied to …
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