Doctoral thesis (Dissertations and theses)
Connectivity percolation and thin film growth containing rods
Dixit, Mohit
2018
 

Files


Full Text
PHD Thesis User Guide- EN - 20140108.pdf
Author postprint (1.28 MB)
Download

All documents in ORBilu are protected by a user license.

Send to



Details



Keywords :
Percolation; Nanorods; Thin films
Abstract :
[en] The evolution of structure in thin films is usually discussed using a kinetic description. This description, mainly developed for metallic films at low temperature, may not be applicable at higher temper- atures as the film grown is close to the equilibrium where the bulk and surface thermodynamics play an essential role, e.g. in case of deposition of organic molecules. Weaker intermolecular interactions and molecular anisotropy add to the complexity of understanding the structure of a growing film. In this thesis, we analyze simplified, coarse–grained models which have potential for addressing the interplay of equilibrium phases and structure formation using Monte Carlo (MC) simulations. Anisotropic particles are modeled by rods with steric exclusion (hard–rods), mutual attractions and interactions with a substrate. First, investigations are shown for formation of the films that con- tain rods, which have mutual attractions and substrate interaction, using MC simulations and kinetic growth model. The model de- scribed by kinetic rate equations requires microscopic quantities as input parameters such as the deposition rate, diffusion constant, and attachment and detachment rates. These parameters are extracted from MC simulations, and we compare simulated growth dynamics to predictions by rate equations. It is observed that the widely ac- cepted strategy of adopting simple kinetic rate equations to specific film growth problems fails in the case of systems with orientational degrees of freedom, such as most organic semiconductor materials. Next, by analyzing the hard–rod monolayer case, the equilibrium properties are obtained which serve as a template for growth stud- ies. Additionally, the MC simulations are compared with classical density functional theory and lattice-based simulations which allow a good methodological control in order to study more complicated and detailed models. In equilibrium, a continuous “standing–up" transition is observed with or without interactive substrate, while the equilibrium properties of the monolayer dominate growth dy- namics. Lastly, and relevant to the charge transport properties of a film, we investigated connectivity percolation in suspensions of attractive rods using the same MC simulation methods mentioned above. The simulation results are then compared with connectivity percolation theory.
Disciplines :
Physics
Author, co-author :
Dixit, Mohit ;  University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Language :
English
Title :
Connectivity percolation and thin film growth containing rods
Defense date :
21 March 2018
Number of pages :
91
Institution :
Unilu - University of Luxembourg, Luxembourg
Degree :
Docteur de l'université du Luxembourg en physique
Promotor :
Schilling, Tanja
President :
Jury member :
van der Schoot, Paul
Poulin, Philippe
Schmidt, Thomas 
Focus Area :
Physics and Materials Science
FnR Project :
FNR9476226 - Film Growth, 2014 (01/07/2015-30/06/2018) - Jan Peter Felix Lagerwall
Name of the research project :
Film growth
Funders :
FNR - Fonds National de la Recherche [LU]
Available on ORBilu :
since 05 March 2019

Statistics


Number of views
149 (19 by Unilu)
Number of downloads
69 (13 by Unilu)

Bibliography


Similar publications



Contact ORBilu