List of Figures

 

1 Introduction

 

Figure 1.1 The structure of diamond

Figure 1.2 The structure of graphite

Figure 1.3 Buckminster Fullerene, C60

Figure 1.4 The phase diagram of carbon

Figure 1.5 An energy diagram of selected states in
the band gap of diamond

 

 

2 Growth and Characterisation

 

Figure 2.1 A schematic diagram of the gas lines which fed the diamond CVD chamber

Figure 2.2 A photograph of the diborane dilution assembly

Figure 2.3 A photograph of the deposition chamber

Figure 2.4 A photograph of the deposition chamber showing the internal assembly after a deposition run

Figure 2.5 A schematic diagram of a three layer metal top contact

Figure 2.6 A schematic diagram of a single layer metal bottom contact

Figure 2.7 A positive ion time-of-flight SIMS spectrum

Figure 2.8 A negative ion time-of-flight SIMS spectrum

Figure 2.9 A positive ion time-of-flight SIMS spectrum (a)

Figure 2.10 A positive ion time-of-flight SIMS spectrum (b)

Figure 2.11 A positive ion time-of-flight SIMS spectrum (c)

Figure 2.12 A positive ion time-of-flight SIMS spectrum (d)

Figure 2.13 A positive ion time-of-flight SIMS spectrum of the graphite control

Figure 2.14 SIMS spectra plotted relative to the undoped control sample (a)

Figure 2.15 The surface of a HFCVD diamond film showing a square facets and a twinned crystallite [B13]

Figure 2.16 The surface of a HFCVD diamond film [B13]

Figure 2.17 The surface of a HFCVD diamond film showing uniform coverage over the substrate [B13]

Figure 2.18 A cross-section of a diamond film [B13]

Figure 2.19 A diamond film grown in an atmosphere containing 1.4% methane [sample B6]

Figure 2.20 A diamond film grown in an atmosphere containing 2.8% methane [sample B8]

Figure 2.21 A cross-sectional view of a diamond films grown with quadruple the normal concentration of methane in the gas phase [sample B8]

Figure 2.22 A cross-sectional view of an early run [B1]

Figure 2.23 A continuous diamond film [sample B142a]

Figure 2.24 Incomplete surface coverage at the edge of a thin diamond film [sample B142a]

Figure 2.25 Individual crystallites that have started to coalesce to form a continuous film [sample B142a]

Figure 2.26 Industrial MPACVD diamond (undoped)

Figure 2.27 Industrial MPACVD diamond (undoped)

Figure 2.28 A cross-section of a free-standing industrial MPACVD diamond film

Figure 2.29 SEM image showing large crystallites [B141b]

Figure 2.30 SEM image showing growth of a thin diamond film [sample B141b]

Figure 2.31 SEM image showing a cross-section of a thin diamond film [sample B141b]

Figure 2.32 A schematic diagram of sample B147a

Figure 2.33 optical microscopy image of the central section (zone 3) 50 objective lens [sample B147a]

Figure 2.34 optical microscopy image of the central section (zone 3) 50 objective lens [sample B147a]

Figure 2.35 optical microscopy image of the central section (zone 3) 50 objective lens [sample B147a]

Figure 2.36 optical microscopy image of the central section (zone 3) 50 objective lens [sample B147a]

Figure 2.37 optical microscopy image of the central section (zone 3) 20 objective lens [sample B147a]

Figure 2.38 SEM image of the central section (zone 3) [sample B147a]

Figure 2.39 SEM image of the central section (zone 3) [sample B147a]

Figure 2.40 optical microscopy image of an end sections (zone 5) 50 objective lens showing limited diamond growth [sample B147a]

Figure 2.41 optical microscopy image of an end sections (zone 5) 50 objective lens showing limited diamond growth [sample B147a]

Figure 2.42 optical microscopy image showing partial diamond growth, 50 objective lens [B147a]

Figure 2.43 optical microscopy image of an end sections (zone 5) 20 objective lens [sample B147a]

Figure 2.44 SEM image of a diamond end sections (zone 5) [sample B147a]

Figure 2.45 SEM image of one of the isolated diamond crystallites [sample B147a]

Figure 2.46 optical microscopy image of an sections (zone 1) 50 objective lens showing partial diamond growth [sample B147a]

Figure 2.47 optical microscopy image of an sections (zone 1) 50 objective lens showing partial diamond growth [sample B147a]

Figure 2.48 optical microscopy image of an end section (zone 1) 20 objective lens showing partial diamond growth [sample B147a]

Figure 2.49 optical microscopy image of an end section (zone 1) 20 objective lens showing partial diamond growth [sample B147a]

Figure 2.50 SEM image of one a end sections (zone 1) showing partial diamond growth [sample B147a]

Figure 2.51 the boundary between zones 4 and 5 ( 20 lens) [sample B147a]

Figure 2.52 the boundary between zones 4 and 5 ( 10 lens) [sample B147a]

Figure 2.53 the boundary between zones 1 and 2 ( 10 lens) [sample B147a]

Figure 2.54 the boundary between zones 1 and 2 ( 10 lens) [sample B147a]

Figure 2.55 the boundary between zones 3 and 4 ( 20 lens) [sample B147a]

Figure 2.56 the boundary between zones 2 and 3 ( 20 lens) [sample B147a]

Figure 2.57 the boundary between zones 2 and 3 ( 10 lens) [sample B147a]

Figure 2.58 SEM image of the boundary between zones 4 and 5 [sample B147a]

Figure 2.59 SEM image of the boundary between zones 1 and 2 [sample B147a]

Figure 2.60 SEM image of the boundary between zones 1 and 2 [sample B147a]

Figure 2.61 Raman spectrum of a type IIb natural diamond

Figure 2.62 Raman spectrum of a poor quality undoped MPACVD diamond film

Figure 2.63 Raman spectrum of boron doped diamond [sample B128a]

Figure 2.64 Raman spectrum of boron doped diamond [sample B128b]

Figure 2.65 Raman spectrum of boron doped diamond [sample B129a]

Figure 2.66 Raman spectrum of boron doped diamond [sample B130b]

Figure 2.67 Raman spectrum of boron doped diamond [sample B140a]

Figure 2.68 Raman spectrum of boron doped diamond [sample B140b]

 

3 Electrical Contacts

 

Figure 3.1 The Metal-Semiconductor Interface

Figure 3.2 A schematic diagram of the evaporator

Figure 3.3 Current-Voltage characteristics for a moderately doped diamond film, 2 Ag dag contacts [B111]

Figure 3.4 Current-Voltage characteristics for a low doped diamond film with 2 Ag dag contacts [B112]

Figure 3.5 Current-Voltage characteristics [B111 & B112]

Figure 3.6 Current-Voltage characteristics for low doped films, 2 Au contacts [B128a & B128b]

Figure 3.7 Current-Voltage characteristics for oxidised films, 2 Au contacts [B123a & B123b]

Figure 3.8 Current-Voltage characteristics, 3LM contacts [sample B122]

Figure 3.9 Current-Voltage characteristics, TiUL contacts [sample B174a]

 

4 Standard Electrochemical Theory

 

Figure 4.1 Current density as a function of overpotential for a metal

Figure 4.2 Schematic Energy Diagram for a Metal-Solution Interface

Figure 4.3 Schematic Energy Diagram for a Semiconductor-Solution Interface

Figure 4.4 Current density as a function of overpotential for a semiconductor

Figure 4.5 Schematic Energy Diagram for a Heavily Doped Semiconductor-Solution Interface

Figure 4.6 Current density as a function of overpotential for a heavily doped semiconductor

Figure 4.7 Diagram of electron transfer via a surface state

Figure 4.8 Forward Bias and Conventional Electrochemical Current

Figure 4.9 Schematic Energy Diagram at positive potential

 

5 The Electrochemistry of Highly Doped Diamond Films

 

Figure 5.1 A schematic diagram of an electrochemistry cell

Figure 5.2 A schematic diagram of a reference electrode

Figure 5.3 A schematic diagram of a Pt counter electrode

Figure 5.4 CV 1 M HNO3, 2 M NaCl, 50 mV/s [B67]

Figure 5.5 CV 3 mM 4-aminophenol, 0.5 M H2SO4 [B67]

Figure 5.6 CV 3 mM C6H7NO,0.5 M H2SO4 50 mV/s [B67]

Figure 5.7 CV 3 mM K4[Fe(CN)6], 1 M KCl [B69]

Figure 5.8 CV 3 mM K4[Fe(CN)6], 1 M KCl 50 mV/s [B69]

Figure 5.9 CV 3 mM K4[Fe(CN)6] , day 1 [B107]

Figure 5.10 CV 3 mM K4[Fe(CN)6] , day 4 [B107]

Figure 5.11 CV 3 mM K4[Fe(CN)6] , day 7 [B107]

Figure 5.12 CV 3 mM K4[Fe(CN)6] , all days [B107]

Figure 5.13 CV 10 mM Fe2+, 10 mM Fe3+, 1 M H+ [B107]

Figure 5.14 CV Fe2+/ Fe3+, 50 mV/s [B107]

Figure 5.15 CV 10 mM Fe2+, 10 mM Fe3+, 1 M H+ [Pt WE]

Figure 5.16 CV Fe2+/ Fe3+, compare sample B107 with Pt

Figure 5.17 Mott-Schottky plots [sample B107]

Figure 5.18 AC Impedance plot, Mod(Z) [sample B107]

Figure 5.19 AC Impedance plot, q [sample B107]

Figure 5.20 CV 10 mM Fe2+, 10 mM Fe3+, 1 M H+ [B102]

Figure 5.21 CV Fe2+/ Fe3+, 5 mV/s [B102]

Figure 5.22 AC Impedance plot, Mod(Z) [sample B102]

Figure 5.23 AC Impedance plot, q [sample B102]

Figure 5.24 AC Impedance plot, bode plots [sample B102]

Figure 5.25 AC Impedance, bode plots, concn expts [B102]

 

6 The Electrochemistry of Low Doped Diamond Films

 

Figure 6.1 CV 10 mM Fe2+, 10 mM Fe3+, 1 M H+, O term, 3LM contact, all rates [B131a]

Figure 6.2 CV 10 mM Fe2+, 10 mM Fe3+, 1 M H+, O term, 3LM contact, 5 mV/s [B131a]

Figure 6.3 CV 10 mM Fe2+, 10 mM Fe3+, 1 M H+, 50 mV/s [Pt WE]

Figure 6.4 CV 10 mM Fe2+, 10 mM Fe3+, 1 M H+, 50 mV/s [B131a & Pt WE]

Figure 6.5 CV 0.3 mM Fe(CN)63-, 0.3 mM Fe(CN)64-, 1 M Cl-, O term, 3LM [B131a]

Figure 6.6 CV 0.3 mM Fe(CN)63-, 0.3 mM Fe(CN)64-, 1 M Cl-, O term, 5 mV/s, 3LM [B131a]

Figure 6.7 CV 0.3 mM Fe(CN)63-, 0.3 mM, Fe(CN)64-, 1 M Cl-, 50 mV/s, 3LM [Pt WE]

Figure 6.8 CV 0.3 mM Fe(CN)63-, 0.3 mM, Fe(CN)64-, 1 M Cl-, 50 mV/s [B131a & Pt WE]

Figure 6.9 CV 0.3 mM Fe(CN)63-, 0.3 mM, Fe(CN)64-, 1 M Cl-, O term, 3LM, all rates [B129b]

Figure 6.10 CV 0.3 mM Fe(CN)63-, 0.3 mM, Fe(CN)64-, 1 M Cl-, O term, 3LM, 25 mV/s [B129b]

Figure 6.11 CV 10 mM Eu3+, 1 M, H+, 1 M Cl-, O term, 3LM, all rates [B129b]

Figure 6.12 CV 10 mM Eu3+, 1 M, H+, 1 M Cl-, O term, 3LM, 5 mV/s [B129b]

Figure 6.13 CV 10 mM Fe(CN)63-, 10 mM, Fe(CN)64-, 1 M Cl-, H term, TiUL, all rates [B144a]

Figure 6.14 CV 10 mM Fe(CN)63-, 10 mM, Fe(CN)64-, 1 M Cl-, H term, TiUL, 5 mV/s [B144a]

Figure 6.15 CV 10 mM Fe(CN)63- / Fe(CN)64-,1 M Cl-, H term, TiUL, all rates, day 3 [B144a]

Figure 6.16 CV 10 mM Fe(CN)63- / Fe(CN)64-,1 M Cl-, H term, TiUL, 5 mV/s, day 3 [B144a]

Figure 6.17 CV 10 mM Fe2+, 10 mM Fe3+,1 M H+, 3LM, all rates, day 3 [B134b]

Figure 6.18 CV 10 mM Fe2+, 10 mM Fe3+,1 M H+, 3LM, 100 mV/s, day 3 [B134b]

Figure 6.19 CV 10 mM Fe(CN)63-, 10 mM, Fe(CN)64-, 1 M Cl-, 3LM, all rates [B134b]

Figure 6.20 CV 10 mM Fe(CN)63-, 10 mM, Fe(CN)64-, 1 M Cl-, 3LM, 25 mV/s [B134b]

Figure 6.21 CV 10 mM Fe(CN)63- / Fe(CN)64-, 1 M Cl-, 3LM, 200 mV/s, effect of exposure [B134b]

Figure 6.22 CV 10 mM Fe(CN)63- / Fe(CN)64-, 1 M Cl-, 3LM, all rates, fresh area exposed [B134b]

Figure 6.23 CV 10 mM Fe(CN)63- / Fe(CN)64-, 1 M Cl-, 3LM, 5 mV/s, fresh area exposed [B134b]

Figure 6.24 CV 10 mM Fe(CN)63-, 10 mM, Fe(CN)64-, 1 M OH-, 3LM, all rates [B134b]

Figure 6.25 CV 10 mM Fe(CN)63-, 10 mM, Fe(CN)64-, 1 M OH-, 3LM, 5 mV/s [B134b]

Figure 6.26 CV 10 mM Fe(CN)63- / Fe(CN)64-,1 M Cl-, 3LM, 200 mV/s, effect of oxidation [B134b]

Figure 6.27 CV 10 mM Fe(CN)63- / Fe(CN)64-,1 M Cl-, 3LM, 100 mV/s, effect of oxidation [B134b]

Figure 6.28 CV 10 mM Fe(CN)63-, 10 mM Fe(CN)64-, 1 M Cl-, 200 mV/s & 50 mV/s [Pt]

Figure 6.29 CV 10 mM Fe(CN)63-, 10 mM Fe(CN)64-, 1 M Cl-, 50 mV/s [Pt]

Figure 6.30 CV 10 mM Fe(CN)63-, 10 mM Fe(CN)64-, 1 M OH-, 200 mV/s & 50 mV/s [Pt]

Figure 6.31 CV 10 mM Fe(CN)63-, 10 mM Fe(CN)64-, 1 M OH-, 50 mV/s [Pt]

Figure 6.32 CV 10 mM Fe(CN)63-, 10 mM Fe(CN)64-, 1 M OH- or 1 M Cl- 50 mV/s [Pt]

Figure 6.33 CV 1 M Cl-, equimolar Fe(CN)63- & Fe(CN)64- 100 mV/s, concentration experiment [B146b]

Figure 6.34 Mott-Schottky plots, O term, 3LM [B134b]

 

7 The Electrochemistry of Low Doped Diamond Films

 

Figure 7.1 Energy level diagram showing the band edges and the energy levels of redox species

Figure 7.2 Reaction at a Hydrogen Terminated Surface

Figure 7.3 Reaction at an Oxygen Terminated Surface

Figure 7.4 Equivalent circuit for surface mediated transfer

Figure 7.5 Mathcad plot of the j - dV relationship case where |j0H| >> |j|

Figure 7.6 Mathcad plot of the j - dV relationship case where |j0H| << |j|

Figure 7.7 Mathcad plot of the j - dV relationship case where |j0H| << |j|

Figure 7.8 Mathcad plot of the j - dV relationship case where |j0SC| >> |j| and j j0H

Figure 7.9 Mathcad plot of the j - dV relationship intermediate values

Figure 7.10 Mathcad plot of the j - dV relationship intermediate values

Figure 7.11 Mathcad plot of the j - dV relationship comparison, small scale

Figure 7.12 Mathcad plot of the j - dV relationship comparison, large scale

Figure 7.13 Mathcad plot of the j - dV relationship

Figure 7.14 Mathcad plot of impedance equation for open circuit conditions

Figure 7.15 Mathcad plot of impedance equation at various potentials

 

8 Intensity Modulated Photocurrent Spectroscopy

 

Figure 8.1 The IMPS Set-up

Figure 8.2 IMPS, 1 mM Fe2+, 1 mM Fe3+, 1 M H+ 470 nm [B121a]

Figure 8.3 IMPS, 1 mM Fe2+, 1 mM Fe3+, 1 M H+ 430 nm [B121a]

Figure 8.4 IMPS, 1 mM Fe2+, 1 M H+, 470 nm [B121a]

Figure 8.5 IMPS, 1 mM Fe2+, 1 M H+, 430 nm [B121a]

Figure 8.6 IMPS, 1 mM Fe3+, 1 M H+, 470 nm [B121a]

Figure 8.7 IMPS, 1 mM Fe3+, 1 M H+, 430 nm [B121a]

Figure 8.8 IMPS, near OCP, 770 nm & 730 nm [B121a]

Figure 8.9 IMPS, near OCP, 730 nm [B121a]

Figure 8.10 Diagram of photogenerated electrons at the diamond-electrolyte interface

Figure 8.11 Mathcad plot of the j - dV relationship (dark and illuminated)

Figure 8.12 Mathcad plot of IMPS equation