X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=thesis%2Fthesis.tex;h=2f54eb942b2a654ddbbc4652c09f454ba3cf6003;hb=5545f4fe8caf6b12a140ebf9c33ed0b1755b1750;hp=f75eedd98e3a640c74efff27140cf1855ece1ff1;hpb=26390cae7a7cf4af40e3485e773eeb909c27ca78;p=matches%2Fhonours.git diff --git a/thesis/thesis.tex b/thesis/thesis.tex index f75eedd9..2f54eb94 100644 --- a/thesis/thesis.tex +++ b/thesis/thesis.tex @@ -1,380 +1,132 @@ -\documentclass[10pt]{article} +\documentclass[a4paper,12pt,titlepage]{report} +\linespread{1.3} +\usepackage{setspace} +\onehalfspacing + +%\usepackage{natbib} +\usepackage{makeidx} \usepackage{graphicx} \usepackage{caption} -\usepackage{amsmath} % needed for math align -\usepackage{bm} % needed for maths bold face - \usepackage{graphicx} % needed for including graphics e.g. EPS, PS -\usepackage{fancyhdr} % needed for header - +%\usepackage{subfigure} +\usepackage{rotating} +%\usepackage{lscape} +\usepackage{pdflscape} % Needed for landscaping - in pdf viewer +\usepackage{verbatim} +\usepackage{amsmath, amsthm,amssymb} +\usepackage{mathrsfs} \usepackage{hyperref} - \topmargin -1.5cm % read Lamport p.163 - \oddsidemargin -0.04cm % read Lamport p.163 - \evensidemargin -0.04cm % same as oddsidemargin but for left-hand pages - \textwidth 16.59cm - \textheight 21.94cm - %\pagestyle{empty} % Uncomment if don't want page numbers - \parskip 7.2pt % sets spacing between paragraphs - %\renewcommand{\baselinestretch}{1.5} % Uncomment for 1.5 spacing between lines - \parindent 0pt % sets leading space for paragraphs +\usepackage{epstopdf} +\usepackage{float} + + + +\newtheorem{theorem}{Theorem}[section] +\newtheorem{lemma}[theorem]{Lemma} +\theoremstyle{definition}\newtheorem{definition}[theorem]{Definition} +\newtheorem{proposition}[theorem]{Proposition} +\newtheorem{corollary}[theorem]{Corollary} +\newtheorem{example}{Example} +\theoremstyle{remark}\newtheorem*{remark}{Remark} + +\newcommand{\Phid}[0]{\dot{\Phi}} +\newcommand{\Phib}[0]{\bar{\Phi}} +\newcommand{\de}[0]{\delta} +\newcommand{\deb}[0]{\bar{\delta}} + +\newcommand{\that}[0]{\hat{\theta}} \newcommand{\vect}[1]{\boldsymbol{#1}} % Draw a vector \newcommand{\divg}[1]{\nabla \cdot #1} % divergence \newcommand{\curl}[1]{\nabla \times #1} % curl \newcommand{\grad}[1]{\nabla #1} %gradient \newcommand{\pd}[3][ ]{\frac{\partial^{#1} #2}{\partial #3^{#1}}} %partial derivative -%\newcommand{\d}[3][ ]{\frac{d^{#1} #2}{d #3^{#1}}} %full derivative +\newcommand{\der}[3][ ]{\frac{d^{#1} #2}{d #3^{#1}}} %full derivative \newcommand{\phasor}[1]{\tilde{#1}} % make a phasor \newcommand{\laplacian}[1]{\nabla^2 {#1}} % The laplacian operator -\usepackage{color} -\usepackage{listings} - -\definecolor{darkgray}{rgb}{0.95,0.95,0.95} -\definecolor{darkred}{rgb}{0.75,0,0} -\definecolor{darkblue}{rgb}{0,0,0.75} -\definecolor{pink}{rgb}{1,0.5,0.5} -\lstset{language=Java} -\lstset{backgroundcolor=\color{darkgray}} -\lstset{numbers=left, numberstyle=\tiny, stepnumber=1, numbersep=5pt} -\lstset{keywordstyle=\color{darkred}\bfseries} -\lstset{commentstyle=\color{darkblue}} -%\lstset{stringsyle=\color{red}} -\lstset{showstringspaces=false} -\lstset{basicstyle=\small} +%\usepackage{endfloat} +%\nomarkersintext +\pagestyle{plain} +\topmargin -0.6true in +\textwidth 15true cm +\textheight 9.5true in +\oddsidemargin 0.25true in +\evensidemargin 0.25true in +\headsep 0.4true in -\begin{document} - +\usepackage{fancyheadings} \pagestyle{fancy} -\fancyhead{} -\fancyfoot{} - -\fancyhead[LO, L]{} -\fancyfoot[CO, C]{\thepage} - -%\title{\bf Characterisation of nanostructured thin films} -%\author{Sam Moore\\ School of Physics, University of Western Australia} -%\date{April 2012} -%\maketitle - -\begin{center} - B.Sc. (Hons) Physics Project \par - {\bf \Large Thesis} \par - Samuel Moore \\ - School of Physics, University of Western Australia \\ - April 2012 -\end{center} -\section*{Characterisation of Nanostructured Thin Films} -{\bf \emph{Keywords:}} surface plasmons, nanostructures, spectroscopy, metallic-blacks \\ -{\bf \emph{Supervisers:}} W/Prof. James Williams (UWA), Prof. Sergey Samarin (UWA) \\ - - -%\tableofcontents - -\section*{Acknowledgements} -\begin{itemize} - \item Sergey Samarin - \item Jim Williams - \item Paul Guagliardo - \item Nikita Kostylev - \item Workshop (for producing electron gun mount?) - \item Peter Hammond (?) -\end{itemize} - -\section{Introduction} -\begin{itemize} - \item Waffle about motivation for the project - \begin{itemize} - \item Metal-Black films may have application for ... something. - \begin{itemize} - \item Radiometer vanes, IR detectors - \item Number of applications where high absorbance into IR is required - \item These have all been studied before though. - \end{itemize} - \item The electron spectra of metal-blacks have not yet been examined. - \item Remarkable difference between Metal-Black films (bad vacuum) and normal metal films (UHV) - \begin{itemize} - \item No (detailed/satisfactory) explanation (that I can find...) for difference - \end{itemize} - \item Talk about plasmonic based computing? Moore's law? Applications to thin film solar cells? - - \end{itemize} - \item Specific aims of project - \begin{enumerate} - \item Surface density of states / band structure of Black-Au films using TCS (The main aim) - \item Identification of plasmonic effects in Black-Au films (?) (If they even exist!) - \begin{itemize} - \item Identify plasmonic effects in Au and Ag films with Ellipsometry (this is fairly simple to do) - \end{itemize} - \item Combination of Ellipsometry and TCS to characterise thin films (not just Black-Au) - \begin{itemize} - \item Ie: How can one technique be used to support the other? - \end{itemize} - \end{enumerate} - \item Structure of thesis -\end{itemize} - -\section{Overview of Theory} -Summarise the literature, refer to past research etc - -\subsection{Electron Spectra of a Surface} -\begin{itemize} - \item Description of the near surface region - \begin{itemize} - \item All real solids occupy finite volumes in space. - \item The surface of a solid is important because interactions between the solid and its surroundings occur in the near surface region. - \item Characterised physically by: - \begin{itemize} - \item Termination of periodic crystal lattice - \item Violation of geometric order - \item Distortion of interatomic distances and hence interaction forces - \item There is a transition ``near surface'' region between bulk and surface properties, roughly 5 atomic distances. - \end{itemize} - \item Potential seen by an electron at a surface can differ greatly from the bulk - \item $\implies$ the electron spectra of the near surface region differs from the bulk spectra - \item Simplest case: Step potential at surface. - - \end{itemize} +\addtolength{\headheight}{2.5pt} +\renewcommand{\chaptermark}[1]{\markboth{\thechapter~~#1}{}} +\renewcommand{\sectionmark}[1]{\markright{\thesection~~#1}{}} +\ifthenelse{\boolean{@twoside}} +{ + \rhead[\bfseries \rightmark]{\bfseries \thepage} + \lhead[\bfseries \leftmark]{\bfseries \thepage} + \addtolength{\headwidth}{\marginparsep} + \addtolength{\headwidth}{\marginparwidth} +}{ + \lhead{\bfseries \leftmark} + \rhead{\bfseries \thepage} +} +\cfoot{} + +%--------------------------------------------------------- +%--------------------------------------------------------- +\begin{document} - \item The Electron Spectra - \begin{itemize} - \item Electron Spectra describes the energy eigenstates for an electron in a Bulk or Surface potential - \item Characterised by - \begin{enumerate} - \item Energy dispersion $E(\vect{k})$ - \begin{itemize} - \item Dependence of Energy on electron wave vector - \item Obtained theoretically by solving Scrhrodinger's Equation - \item For a free electron gas, $E = \frac{\hbar^2 k^2}{2m} - \item Periodic potential in bulk solid leads to band gap structure of $E(\vect{k})$ - \item Periodic potential $\implies$ E is periodic. Only needs to be defined in first Brillouin zone. - \end{itemize} - \item Density of States $N(E)$ - \begin{itemize} - \item $N(E) = \frac{\Delta N}{\Delta E} = \frac{1}{4\pi^3}\int_S\left(\der{E}{k}\right)^{-1} dS$ - \item Integral is in momentum space over the isoenergetic surface of energy $E$ - \item For a free electron gas, $N(E) = $ - \end{itemize} - \end{enumerate} - \end{itemize} +\include{titlepage/Titlepage} % This is who you are - \item Surface states - \begin{itemize} - \begin{enumerate} - \item Simplest model: Step potential - \item Tamm States: Periodic potential in solid, free space outside, jump at surface - \begin{itemize} - \item Energy eigenvalues lie in the forbidden band of the bulk spectra - \item Attenuation of eigenvalues from surface to vacuum, oscillation of state within surface - \item Max electron density occurs on the crystal surface - \end{itemize} - \item Shockley states: Potential of surface and bulk cells equal - \begin{itemize} - \item Corresond to free valences (dangling bonds) at the surface - \end{itemize} - \end{enumerate} - \item Tamm and Shockley states arise from two extreme models (large change and small change respectively between bulk and surface). In reality, a combination of Tamm and Shockley states appear. - \item These states arise from termination of the lattice; but the surface cells are assumed undistorted - \item In reality surface cells are distorted by relaxation and reconstruction of the surface - \end{itemize} +\newpage - \item Main reference: Komolov "Total Current Spectroscopy" - \item "Solid State Physics" textbooks and "Electron Spectroscopy" textbooks -\end{itemize} +%include{acknowledgments/Acknowledgments} % This is who you thank -\subsection{Plasmonics} -I really think I should actually find plasmonic effects before writing too much about them... -\begin{itemize} - \item Charge density oscillations - \item Surface and bulk plasmons - \item Pines and Bohm - \item Review article from T.W.H Oates et al about using Ellipsometry to characterise plasmonic effects -\end{itemize} +\newpage -\subsection{Metallic-Black Thin Films} -\begin{itemize} - \item How they are made (bad vacuum, in air or a noble gas) - \begin{itemize} - \item If made in air, there are usually tungsten oxides present (from filament). Refer to paper by Pfund. - \end{itemize} - \item Structural difference between Black-Au and ``Shiny'' (need a better term) Au - \begin{itemize} - \item Can include electron microscopy images? - \item An actual photograph of a Black-Au film? Not necessary? - \end{itemize} - \item Pfund (earliest publisher, preparation and general properties) - \item Louis Harris (most research in 50s and 60s) - \begin{itemize} - \item L. Harris mostly did transmission spectroscopy in the far infra red (well beyond the ellipsometer and Ocean Optics spectrometer ranges) - \item The really crappy measurements I did with the Ocean Optics spectrometer seem to agree with these measurements - \begin{itemize} - \item L. Harris' $\lambda$ has a range of 1nm to $100\mu$m; my measurements are only to $1\mu$m - \item Agreement in first $1\mu$m anyway - \item I should probably re-do those measurements with a less crappy setup, if I actually want to use them - \end{itemize} - \item Harris related the optical properties to the structure of the film (condensor strands) via the electronic properties - \end{itemize} - \item Plasmonic effects - Deep R. Panjwani (honours thesis) - \begin{itemize} - \item Not sure if I can use an honours thesis as a reference. - \item Concluded that surface plasmon resonance in Black-Au film on solar cells lead to increase in solar cell efficiency - \item Used simulation that modelled Black-Au film as spherical balls to show E field increased by plasmon resonance - \begin{itemize} - \item Was this model appropriate? Black-Au is more ``smoke'' or ``strand'' like according to other references. Images also do not show ``blob'' like structure. - \end{itemize} - \item Need to read this reference more thoroughly - \end{itemize} -\end{itemize} +%\include{abstract/Abstract} % This is your thesis abstract -\section{Experimental Techniques} +\pagenumbering{roman} +\newpage +%--------------------------------------------------------- +% Do the table of Contents and lists of figures and tables +%--------------------------------------------------------- +\tableofcontents +\markboth{}{} +\newpage -\subsection{Preparation of samples} -\begin{itemize} - \item Black-Au - 1e-2 mbar vacuum - \item ``Shiny'' - 1e-6 / 1e-7 - \item Current of ~3.5A through W wire filament spot welded onto Ta strips in turn spot welded to Mo posts - \item Voltage through filament is ~1 V; quote the power? - \item Filament isotropically coats sample with desired material. - \item Possibly get a curve of Au thickness estimated with Ellipsometry vs exposure time? - \begin{itemize} - \item Probably too much work and too unreliable - \item Maybe do it, but only use 2/3 data points - \item Low priority - \end{itemize} -\end{itemize} +\pagenumbering{arabic} +%--------------------------------------------------------- +%--------------------------------------------------------- +%Include the chapters! -\subsection{Total Current Spectroscopy} -\begin{itemize} - \item - \item Total Current Spectroscopy methods measure the total current of secondary electrons as a function of primary electron energy. - \item These methods are distinguished from ``differential'' methods (such as Auger electron spectroscopy and energy loss spectroscopy) which measure the secondary electron spectrum at a fixed primary electron energy. - \item - \begin{itemize} - \item Low energy beam of electrons incident on sample - \item Measure slope of resulting I-V curve - \item Relate to density of states and electron band structure (Komolov chapter 3.2) - \end{itemize} - \item Description of apparatus - \begin{itemize} - \item Electron gun and filament - \item Electron gun control box - \item ADC/DAC control box and data processing - \end{itemize} - \item Photographs vs Diagrams - \begin{itemize} - \item Prefer diagrams to photographs - \item Especially for the ADC/DAC control box circuit. Because it looks like a horrible mess. - \end{itemize} -\end{itemize} +\include{chapters/Introduction} -\subsection{Ellipsometry and Transmission Spectroscopy} -\begin{itemize} - \item Overview of techniques - \item Description of apparatus (use VASE manual) - \item Ocean Optics spectrometer? Usable? - \item Application of Ellipsometry to finding plasmonic effects - \begin{itemize} - \item Surface plasmons = E oscillation parallel to surface $\implies$ only $p$ component of light excites plasmons - \end{itemize} -\end{itemize} +\include{chapters/Theory} % This is chapter 1 -\section{Experimental Results and Discussion} -\subsection{TCS Measurements} -\begin{itemize} - \item TCS for Si - \item TCS for Si + Au - \item TCS for Si + Black-Au - \item Affect of preparation pressure on TCS for Si + Black-Au - \item Repeat for Si + Ag and Si + Black-Ag (?) -\end{itemize} +\include{chapters/Techniques} % This is chapter 2 -\subsection{Ellipsometric Measurements} -\begin{itemize} - \item Ellipsometry to estimate thickness of SiO2 layer on Si - \item Estimate thickness of Au/Ag on Si+SiO2 - \item Ellipsometric measurements of Si+Black-Au/Ag - \begin{itemize} - \item Modelling procedures to characterise Black-Au/Ag - \end{itemize} - \item Ellipsometric measurements of Glass+Black-Au/Ag (?) - \item Transmission spectra of Glass+Black-Au/Ag from earlier in year (?) -\end{itemize} +\include{chapters/Results} % etc. -\section{Achievements} -\begin{itemize} - \item Deposition of thin films of Au and Black-Au in vacuum chamber - \item Ellipsometric and spectroscopic measurements on these films - \item Repurpose vacuum chamber for sample preparation and TCS experiments - \item Designed and built electronics for TCS experiments - \begin{itemize} - \item Electron gun control box - \item ADC/DAC box - \end{itemize} - \item Wrote software for data aquisition and data processing -\end{itemize} +\include{chapters/Conclusion} +%\newpage +%--------------------------------------------------------- +\renewcommand{\bibname}{References} +\bibliography{references/refs} +\bibliographystyle{ieeetr} +\addcontentsline{toc}{part}{References} +%--------------------------------------------------------- -\section{General notes} -\subsection{TCS} -\begin{itemize} - \item Optimise setup of gun - \begin{itemize} - \item Emission current. How much does it vary, why does it vary. - \item Why does Is/Ie curve shift with successive sweeps? Does sweep modify sample's surface? - \item Is sample holder acceptable? Are ceramic washers accumulating charge? - \item How do I tell when the setup is optimised... - ``The setup was optimised by looking for an S curve''. Very scientific. - \item The gun was focused on the phosphor screen... and then I turned it around, changing the distance from the gun to the sample. Brilliant. - \end{itemize} - \item Obtain TCS spectra for Si that compares well with literature - \begin{itemize} - \item How to relate TCS spectrum to $n(E)$ and $E(\vect{k})$ - \end{itemize} - \item Prepare Au films, obtain TCS spectra that compares with literature - \item Obtain TCS spectra of Black-Au films - \item Use results to compare properties of films with results from other methods in the literature - \item Uncertainties - \begin{itemize} - \item Oscilloscope measurements of inputs to ADC channels under controlled conditions - \begin{itemize} - \item Expected values are +/-3mV due to ADC channel, +/-300mV due to 610B, +/-1mV due to 602 - \item 610B and 602 will probably be worse because they are ancient - \item There is about 200mV of noise between the GND of the ADC box and the electron control box. - \item How to reduce ground loops? Not much I can do. Rack is now also grounded to water pipe, but this doesn't seem to make a difference. - \end{itemize} - \item Stupid 50Hz AC noise... how to reduce with filters and/or averaging - \end{itemize} - \item Create circuit diagrams for Electron gun circuit - \item Create circuit diagrams for ADC/DAC box - \begin{itemize} - \item Simulate behaviour of circuit - \item Use of instrumentation amplifier on ADC5 to make off-ground measurements - \item Use of low pass filter on ADC5 - \end{itemize} - \item Include references to all datasheets, etc - \item Vacuum chamber - \begin{itemize} - \item Base pressure with rotary pump? Was 1e-3 after 30 minutes at start of year, but probably introduced leaks since then - \item Lowest pressure achieved with turbo pump is 1.1e-7 mbar as of 25/07. - \item Viton gaskets on some seals. Copper on other. - \item Flanges: - \begin{enumerate} - \item View window (large, view of sample \& sputtering filaments) - \item Rotation manipulator \& sample mount - \item Pump inlet - \item Filament flanges 1 (used earlier in year, not anymore) and 2 - \item Inlet with leak valve (for introducing gases into chamber) - \item Vent valve on turbo pump - \item Electron gun flange - \item View window (small, view of back of electron gun) - \end{enumerate} - \end{itemize} -\end{itemize} +% Appendices +\appendix +\include{appendices/tcs_noise} +\include{appendices/electron_optics} +\include{appendices/electron_gun_circuit} +%\include{appendices/data_aquisition} -\pagebreak -\bibliographystyle{unsrt} -\bibliography{thesis} +%--------------------------------------------------------- \end{document}