Table of
Contents
List of Tables
Units
and Nomenclature
1.0 Outline
1.1 The History
of Diamond
1.2 Allotropes
of Carbon
1.3 Properties
of Diamond
1.4 The
Synthesis of Diamond
1.5 Uses of
Diamond
1.5.1 Abrasives
1.5.2 Thermal
Management
1.5.3 Electronic
Devices
1.5.4 Optical
Windows
1.6 The
Electrochemistry of Boron Doped Diamond
1.7 Summary
1.8 Outline of
the Thesis
2 Growth and Characterisation of the Diamond Films
2.0 Outline
2.1 The Choice
of Growth Technique
2.2 The
Reaction Gases
2.3 The Mass
Flow Controllers
2.4 Dilution of
the Diborane Gas
2.5 The
Deposition Chamber
2.6 The
Substrate Heater
2.7 The
Filaments
2.8 The
Substrates
2.9 Electrical
Contacts to the films
2.9.1 Indium/Gallium
Eutectic
2.9.2 Silver
Loaded Epoxy Resin
2.9.3 Three Layer
Metalisation
2.9.4 Titanium
Contacts
2.9.5 Summary
2.10 Typical
Growth Conditions
2.11 Secondary
Ion Mass Spectroscopy
2.12 Scanning
Electron Microscopy
and Optical Microscopy
2.13 Laser Raman
Spectroscopy
2.14
Summary
3.0 Outline
3.1 Introduction
3.2 Fabrication
of Three Layer Metal Contacts
3.3 Fabrication
of Titanium Underlayer Contacts
3.4 Characteristics
of Silver Epoxy Resin Contacts
3.5 Characteristics
of Evaporated Gold Contacts
3.6 Characteristics
of Three Layer Metal Contacts
3.7 Characteristics
of Titanium Underlayer Contacts
3.8 Four Point
Probe Measurements
3.9 Summary
4 Standard
Electrochemical Theory
4.0 Outline
4.1 Metal Electrochemistry
4.2 Normal p-type Semiconductor
Electrochemistry
4.3 Highly Doped Semiconductors
4.4 Surface State Mediated Electrode
Transfer
4.4.1 Contributions to the Applied Potential
4.4.2 Contributions
of the Helmholtz Layer
and the Space Charge Region
4.4.3 Electrical Charge at the Surface
of a Semiconductor Electrode
4.4.4 The Butler-Volmer Equation
4.4.5 Schottky Diode
4.4.6 Model
4.5 Steady State Current
4.6 Summary
5 The
Electrochemistry of Highly Doped Diamond Films
5.0 Outline
5.1 Experimental Set-up
5.1.1 Electrolyte Solutions
5.1.2 Electrochemical Cells
5.1.3 Reference Electrodes
5.1.4 Counter Electrodes
5.1.5 Potentiostats
5.1.6 Faraday Cages
5.2 The Cyclic Voltammetry Technique
5.2.1 Reversible Electrode Dynamics
5.2.2 Irreversible Electrode Dynamics
5.2.3 Quasi-Reversible Electrode Dynamics
5.3 Cyclic Voltammetry in Dilute Nitric
Acid
5.4 Cyclic Voltammetry of 4-Aminophenol
5.5 Cyclic Voltammetry of Potassium
Ferrocyanide
5.6 Cyclic Voltammetry of Ferrous Sulphate
and Ferric Sulphate
5.7 Mott-Schottky Plots
5.8 AC Impedance
5.8 Moderately Doped Films
5.9
Summary
6 The
Electrochemistry of Low Doped Diamond Films
6.0 Outline
6.1 Experimental Set-up
6.2 Surface
Termination
6.3 Cyclic
Voltammetry of oxygen-terminated low-doped diamond
6.3.1 Cyclic Voltammetry of Ferrous Sulphate and Ferric Sulphate
6.3.2 Cyclic Voltammetry of Potassium Ferrocyanide and Potassium
Ferricyanide
6.3.3 Cyclic
Voltammetry of Other Redox Couples
6.4 Cyclic Voltammetry of
hydrogen-terminated low-doped diamond
6.5 Cyclic Voltammetry of
low-doped diamond with indeterminate surface termination
6.5.1
Cyclic
Voltammetry of Ferrous Sulphate and Ferric Sulphate
6.5.2
Cyclic
Voltammetry of Potassium Ferrocyanide and Potassium Ferricyanide in an Aqueous Solution
of Potassium Chloride
6.5.3 Cyclic Voltammetry of Potassium Ferrocyanide and Potassium
Ferricyanide in an Aqueous Solution of Potassium Hydroxide
6.6 Concentration Effects
6.7 Mott-Schottky Plots
6.8 Summary
7 Theoretical
Model for the Electrochemistry
of Boron Doped Diamond
7.0 Outline
7.1 Interpreting
the Metallic Behaviour of Highly Doped Diamond
7.2 Explanation
of the Metallic Behaviour of Highly Doped Diamond
7.2.1 Hydrogen Terminated Diamond
7.2.2 Oxygen Terminated Diamond
7.3 The relationship between current
density and applied potential
7.3.1 Special cases of the current density - applied potential
relationship
7.3.1.1 The case where |j0H| >> |j|
7.3.1.2 The case where |j| >> |j0H|
7.3.1.3 The case where |j0SC| >> |j| and j » j0H
7.3.2 The current density - applied potential relationship at
intermediate values
7.4 AC Impedance and the Surface State
Model
7.5 Interpreting the Semiconductor Behaviour
of Low Doped Diamond
7.6 Summary
8 Intensity
Modulated Photocurrent Spectroscopy
8.0 Outline
8.1 Intensity
Modulated Photocurrent Spectroscopy (IMPS)
8.2 Experimental
Set-up
8.3 Experimental
Results
8.4 Theory
8.4.1 Effect of Constant Illumination on the Current Density
8.4.2
Effect
of Modulated Illumination on the Current Density
8.5 Summary
9.1 Background
9.2 Growth and
Characterisation
9.3 Electrical
Contacts
9.4 Standard
Electrochemical Theory
9.5 Electrochemistry
of Highly and Moderately Doped Diamond Films
9.6 Electrochemistry
of Low Doped Diamond Films
9.7 Electrochemical
Theory for Boron Doped Diamond Films
9.8 Intensity
Modulated Photocurrent Spectroscopy
9.9 Possible Future Work
A Appendix A:
Levels of Impurities
A.1 potassium
chloride, KCl
A.2 potassium
hydroxide, KOH
A.3 sodium
chloride, NaCl
A.4 ferrous
sulphate heptahydrate, FeSO4.7H2O
A.5 ferric
sulphate pentahydrate, Fe(SO4)3.5H2O
A.6 ferric
nitrate nonahydrate, Fe(NO3)3.9H2O
B Appendix B: Summary
of Diamond Growth Runs