"Nanotemplate creation and self-assembly on the (111) surface of gold" by Georgi Nenchev Nenchev

Date of Award

Spring 2008

Project Type

Dissertation

Program or Major

Physics

Degree Name

Doctor of Philosophy

First Advisor

Karsten Pohl

Abstract

Self-assembly on strained metallic interfaces is an attractive option for growing highly ordered, multi-functional nanopatterns. I performed a series of studies in UHV to investigate the processes of ordered growth and self-assembly on Au(111). I did a combined AES/STM study of the formation of ordered networks of Co islands on Au(111) and obtained the conditions for growing uniform, bi-layer Co-terminated clusters. In another STM study I obtained novel results which reveal the particular complexity of CH3SH self-assembly on Au(111). I observed dimerization of the molecules on the FCC areas of an unperturbed Au(111) reconstruction network and the formation of two new continuous ordered phases--an in-plane oriented stripe phase (beta-phase) and an out-of-plane pointing, close-packed phase (&phgr;-phase). These results complement recent theoretical investigations and contribute to an ongoing DFT study of the energetics of the assembly. The cluster growth and the self-assembly processes are successfully combined in achieving selective adsorption of CH 3SH on Co/Au(111) network--a prototype nanotechnology for directed self-assembly of molecular elements on large, multifunctional templates with a nm size unit cell. The thermal evolution of Co/Au(111) system is established, and CH3SH is shown to exhibit a novel interaction which leads to non-dissociative dimerization and to the formation of new ordered phases.

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