Synthesis of Nanomaterials: Mechanisms, Kinetics and Materials Properties

Preface
Contents
Acronyms and Abbreviations
1 Introduction
References
2 Nanomaterials Synthesis Routes
2.1 Introductory Comments
2.2 Basics
2.3 Control Over Nanomaterials Growths
2.4 CVD Route for Synthesis
2.5 MBE Route for Synthesis
2.6 Pulsed Laser Deposition Route for Synthesis
2.7 Solvothermal Route for Synthesis
2.8 ARC Discharge Route for Synthesis
2.9 Differences Between CVD and PVD Techniques
2.10 Sol-Gel Route for Synthesis
2.11 Chemical Beam Epitaxy
2.12 Conclusions
References
3 Catalyst Nanoparticles
3.1 Background
3.1.1 Steps for Nanoparticle Formation
3.1.2 METANOs and SUBSANOs for Growths
3.2 METANO and METANO Synthesis
3.2.1 Synthesis Methods
3.2.2 Synthesis Approaches
3.2.3 Catalytic Reactivity
3.3 SUBSANO and SUBSANO Synthesis
3.3.1 SUBSANO Synthesis by Surface Treatment
3.3.2 SUBSANOs Generated by Stress
3.3.3 SUBSANOs Created by Droplets
3.4 Nanoparticle Surface Composition Called RL Species
3.4.1 Definition
3.4.2 RL Species Composition and Characteristics
3.5 Types of Nanoparticles
3.5.1 Type 1 Nanoparticles
3.5.2 Type 2 Nanoparticles
3.5.3 Type 3 Nanoparticles
3.5.4 Type 4 Nanoparticles
3.6 Effects of Surface, Interface, Size, and Density of Nanoparticles
3.7 Bimetallic Nanoparticles
3.7.1 Structural Diversity of BNPs
3.7.2 BNP Properties Different from the Corresponding Bulk
3.7.3 BNP Based RL Species
3.8 Ostwald Ripening of Nanoparticles
3.9 Functionalization of FECA Nanoparticles
3.10 Lifetime of Feca Metal Nanoparticles
References
4 Pre-synthesis and Synthesis Events
4.1 Basics
4.2 Pre-synthesis Process: Formation of Catalyst Support
4.3 Crucial Synthesis Stages
4.4 Key Synthesis Events
4.4.1 Event 1
4.4.2 Event 2
4.4.3 Surface Activation Barrier
4.4.4 Reaction and Interaction on Nanoparticle Surface
4.4.5 Anisotropic Growth and Nucleation for This Growth
4.4.6 Adhesive Properties of the Nanoparticle Seed
4.4.7 Contact Angle
4.5 The Nanoparticle Core and Shell Structures for Synthesis
4.6 Nanoparticle Periphery with Shell and Hill for Synthesis
4.7 Smaller Nanoparticles Generally Yield SWCNTs
References
5 The VLS Mechanism
5.1 Historical Background
5.2 Important Requirements
5.3 The Eutectic Phase
5.3.1 Formation of Droplet
5.3.2 Incubation Time
5.3.3 Thermodynamic and Kinetic Conditions for Incubation Time
5.3.4 Binary Phase Diagrams
5.3.5 Important Requirements for the Formation of Droplets
5.4 FECA Metal Selection
5.4.1 Possible Selection Criteria
5.4.2 Illustrative Examples
5.5 Growth Dynamics
5.6 Temperature Dependency
5.6.1 Inconsistency in Growth Characteristics
5.6.2 Several VLS Growth Rates Compared
5.6.3 VLS Growth at Eutectic Temperature
5.7 Failures of the VLS Mechanism to Mediate Some Nanowire Growths
5.7.1 Lack of Atomic-Scale Control Over Growth
5.7.2 Silicon Nanowire Growth Rate as Function of Various Growth Parameters
5.7.3 InAs Nanowire Growth Rate as Function of Various Growth Parameters
5.7.4 Defects in Nanowires by the VLS Mechanism
5.7.5 Impact of MET Contamination in Nanowire
5.8 Failures of the VLS Mechanism to Mediate Carbon Nanotube Growths
5.8.1 Location, Shape, and Size of Catalyst Particle During Growth
5.8.2 Crystallographic Relationship During Growth
5.8.3 Presumed Stages of Growth
5.8.4 Possible Mechanism for Growth
5.9 Criteria for Nanomaterial Growths by the VLS Mechanism
5.9.1 Criterion 1
5.9.2 Criterion 2
5.9.3 Criterion 3
5.9.4 Criterion 4
5.9.5 Criterion 5
References
6 Vapor–Solid–Solid Growth Mechanism
6.1 Basics
6.2 Illustrations of Nanowire Growth by the VSS Mechanism
6.2.1 Au-Mediated Low-Temperature ZnO Nanowire Growths
6.2.2 Cu-Mediated Low-Temperature Ge Nanowire Growths
6.2.3 Nanowire Growths via Solid FECA Material
6.2.4 Temperature-Dependent Variation of Nanowire and of MET Catalyzing This Nanowire
6.3 Illustrations of Carbon Nanofiber Growth by the VSS Mechanism
6.4 Illustrations of Carbon Nanotube Growth by the VSS Mechanism
6.5 Strengths of the VSS Mechanism
6.5.1 Superior Crystal-Phase Control
6.5.2 Abrupt Interface Composition
6.6 Controversy and Weaknesses of the VSS Mechanism
6.7 Rate-Limiting Steps During the VSS Growths
6.8 Comparison of VSS Growth Rates with the VLS Growth Rates
6.9 Temperature-Dependent Growths
6.9.1 Temperature-Dependent Growth Rate of Nanowires
6.9.2 Temperature-Dependent Growth Rate of Carbon Nanotubes
References
7 Vapor–Solid Growth Mechanism
7.1 Basics
7.2 Illustrations of Nanowire Growth by the VS Mechanism
7.2.1 Nanowire Growths on Non-stoichiometric SiOz and GeOz Wafer Surfaces
7.2.2 Nanowire Growths on Activated Amorphous Carbon
7.2.3 Nanowire Growths on Au Cluster Surface
7.2.4 Chemical Vapor Deposition of Tungsten Oxide Nanowires
7.2.5 Comparison of Nanowires by the VS and the VSS Mechanisms
7.3 Illustrations of Carbon Nanotube Growths by the VS Mechanism
7.3.1 CNT Growths on Nanosized Diamond
7.3.2 Basics of CNT Growths on Nanosized Diamond
7.3.3 MWCNT Growths on Defective Surfaces
7.3.4 SWCNT Growths on SiO2 Surfaces
7.4 Illustrations of Nanobelt Growth by the VS Mechanism
7.5 Nanomaterial Growth Rates by the VS Mechanism
7.6 The Role of SUBSANO in Nanomaterial Growths
7.7 Growths by Water-Assisted Means
7.7.1 Basics
7.7.2 Effect of Precursor Flow
7.7.3 Effect of Temperature on CNT Growth
References
8 Solution and Supercritical Fluid-Based Growth Mechanisms
8.1 Background
8.2 Various Features of Solution and Supercritical Fluid-Liquid-Solid Mechanisms
8.2.1 Basics
8.2.2 Environment for the Synthesis of III-V Nanowires
8.2.3 Supercritical Fluid Conditions
8.2.4 First Realization of Supercritical Fluid Condition
8.2.5 Inference
8.3 Solution- and Supercritical-Fluid-Based Growth Techniques
8.4 SFLS Nanowire Characteristics
8.4.1 Nanowire Size Distribution
8.4.2 Example of Ge Products from Low-Temperature Reactions
8.4.3 SFLS Growth of Si and Ge Nanowires
8.5 Strengths
8.5.1 Growth of Highly Promising Ge Nanowires
8.5.2 High Crystallinity of Nanowires
8.5.3 Other Advantages
8.6 Weaknesses
8.6.1 Challenges
8.6.2 Low-Temperature Growths
8.6.3 Solution-Phase Mechanisms Inferior to Vapor-Phase Mechanisms
8.6.4 Illustrative Demonstrations of SFLS and SoLS Mechanisms
8.7 SoSS (SFSS) Mechanism
8.7.1 Background
8.7.2 Specifics of the SoSS and the SFSS Mechanisms
8.7.3 Interesting Feature of Chalcogenite Nanoparticles
8.7.4 Nanowire Quality Dependent on Precursor
References
9 Solid–Liquid–Solid Growth Mechanism
9.1 Various Features of the Synthesis
9.1.1 Basics
9.1.2 General Hypothesis for Growths
9.1.3 Why Nanowire Growths Do Not Take Place at T < Tsls
9.2 Why SLS Nanowires Are Often Amorphous or Have Amorphous Shell?
9.3 Illustrations of the Catalyst and Temperature for the SLS Growth
9.4 Illustrations of Oxide and Nitride Nanowires Growth by the SLS Mechanism
9.4.1 SiOz Nanowire Growths
9.4.2 In2O3 Nanowire Growths
9.4.3 Si3N4 Nanowire Growths
References
10 Oxide-Assisted Growth Mechanism
10.1 Introduction
10.1.1 Basics
10.1.2 High-Temperature Reaction, Formation of Clusters, and Their Impacts
10.1.3 Experimental Demonstrations Of The OAG Mechanism
10.2 Advantages and Disadvantages of the OAG Mechanism
10.2.1 Advantages
10.2.2 Disadvantages
10.3 Analysis of the Observed Oxide-Assisted Growths
10.4 Formation of the Oxide Sheath
10.5 Role of Metal in Oxide-Assisted Growth
10.6 Role of Sulfur in Oxide-Assisted Growth
References
11 Self-catalytic Growth (SCG) Mechanism
11.1 Introduction
11.2 Approaches to Obtain Met-Free Nanoparticle Seeds
11.3 Examples of Met-Free Nanowire Growths
11.3.1 Selective Area Epitaxy
11.3.2 CVD Growth of III–V Nitride Nanowires
11.3.3 Vapor Deposition of InAs Nanowires
11.3.4 Patterned Growth of InAs Nanowires
11.3.5 Boron Nitride Nanotube Growths
11.4 Understanding the Self-catalytic Nanowire Growth
11.4.1 Tips, Hillocks, and Roughness Crucial for Growths
11.4.2 Grains and Grain Boundaries Formed Prior to Growths
11.5 Role of Oxide in Nanowire Growth
11.6 Various Stages of Nanowire Growth
11.7 Novelty of the SCG Mechanism
11.8 Differences Between Selective Area Epitaxy and Self-catalytic Growth
11.9 Nanoparticles Crucial for Nanowire Growths
11.9.1 Porous SiOz Film Formed on Substrate
11.9.2 Buffer Layer Formed on Substrate
11.9.3 Both X and XmYn Nanoparticles Can Lead to XmYn Nanowire Growths
11.9.4 Superiority of SEG Mechanism to Other Mechanisms
References
12 VQS Mechanism for Nanomaterials Syntheses
12.1 Forwarding Note
12.2 The Concept of Quasiliquid (Quasisolid) Nanoparticle Surface
12.2.1 Quasiliquid (Quasisolid) Medium Defined
12.2.2 Structure and Morphology of Nanoparticle
12.2.3 Nanoparticle Surfaces Influenced by Various Parameters
12.2.4 Illustrations of Nanoparticle Surfaces
12.3 Surface Coarsening of Nanoparticle Surface
12.3.1 Elements of Surface Coarsening; Tamman and Heutting Temperatures
12.3.2 Basics of Surface Coarsening
12.3.3 Illustrations of Surface Roughness
12.4 Surface Looseness and the Porosity ρc
12.4.1 Effect of Annealing and Temperature on the Opening of Mask
12.4.2 Migration of the RS Source Species and of the Droplets
12.4.3 Illustrations of Nanopores Generated on Nanoparticle Surface
12.5 Melting (Semi-melting) of Nanoparticle Surface
12.5.1 Basics
12.5.2 A Simple Model of Surface Melting
12.5.3 Illustrations of Surface Melting
12.5.4 Possible Causes of Surface Melting
12.6 Nanoparticle Structure and Morphology
12.7 Phase Transition(s) and Phase Separation(s)
12.8 Creation of High-Energy Sites (HETs)
12.9 NP1 and NP2 Nanoparticles
12.9.1 Basic Definitions
12.9.2 Illustrations
12.10 Evidences of Phase Transitions
12.11 Evidences of Phase Transitions and Co-existence of Multiple Phases
12.12 Evidence of Phase Separation
12.13 Experimental Evidences of the Benefits of Surface Treatments
12.13.1 Surface Treatment Yields Surface Amorphicity and Surface Roughness
12.13.2 Surface Treatment Yields Surface Porosity
12.13.3 Optimal Level of Defect and Amorphicity Essential for Nucleation and Growth
12.14 Distinctive Features of Nanomaterials Syntheses by the VQS Mechanism
12.14.1 Transformation from Vapor Phase to Solid Phase
12.14.2 Formation of Intermediate Quasiliquid (Quasisolid) Phase
12.14.3 The Need of Streamlining for Porosity and Growth
12.14.4 Role of Catalyst Support and Dipole Moment in FECA Surface Functionalization
12.14.5 Illustrations of the Role of Catalyst Support in FECA Nanoparticle Surface Functionalization
12.14.6 Amphoteric Characteristics of Catalyst Support Should Be Preferred
12.14.7 Catalyst Support Should Enhance FECA Nanoparticle Surface Disturbance and Polarity
12.15 Nanomaterial Growths by Low-Melting Point Metals
12.16 Nanomaterials Tips
12.17 Concluding Remarks
12.17.1 Surface Energy
12.17.2 Nanomaterials Nucleation
12.17.3 Superiority of the VQS Mechanism
References
13 Growths on METANO Surface by the VQS Mechanism
13.1 Forwarding Note
13.2 Basic Concepts
13.2.1 Formation of RL Species
13.2.2 Phase Transformations and Generations
13.2.3 Possible Events During the Pre-nucleation Stage of Growth
13.3 Illustrative Demonstration of the RL Species
13.3.1 Non-eutectic RL Species Created by Some Oxide-Assisted Growth Experiments
13.3.2 Eutectic RL Species Created by Some Non-oxide-Assisted Growth Experiments
13.3.3 Non-eutectic RL Species Created by Some Non-oxide-Assisted Growth Experiments
13.4 The Role of Surface Energy in the Met-Mediated Growths
13.4.1 Surface Energy Defined
13.4.2 METANO Surface Characteristics
13.4.3 Barrier to the Exchange of Materials on the METANO Surface
13.5 Model for the Role of Surface Energy in the Met-Mediated Growth
13.5.1 Model for the Exchange of Materials
13.5.2 Alternative Model for the Exchange of Materials
13.6 Analyses of the Role of Surface Energy in the Metano-Mediated Growth
13.6.1 Reduced Solubility of METANO Surface
13.6.2 Exchange of Materials on METANO Surface
13.7 Why Are Au-Mediated Si and Ge Nanowire Growths So Successful?
13.7.1 Possible Reasons of Au Being Suitable for the VLS Growths of Si and Ge Nanowires
13.7.2 Reasons for Other Metals not Being Very Suitable for the VLS Growths of Si and Ge Nanowires
13.7.3 Surface Energy, Activation Energy, and Exchange of Materials on METANO Surface
13.8 Carbon Solubility in Metano
13.8.1 Reduced Solubility
13.8.2 Effective Barrier to Exchange of Materials
13.8.3 Important Revelation
13.9 Why CNT Growth Rates with Fe, Co, and Ni Are Very High
13.9.1 Experimental Demonstration
13.9.2 Possible Causes of Said Observations
13.9.3 Possible Causes of Discrepancy Based on Calculated Results
13.9.4 Implication of Higher Solubility of C in Fe, Co, and Ni for SWCNT Growths
13.9.5 Implication of Lower Solubility of C in Fe for MWCNT Growths
13.10 Limit of Growth Rate
13.11 Conclusions
References
14 Growths on SUBSANO Surface by the VQS Mechanism
14.1 Forwarding Note and Basic Concepts
14.1.1 Forwarding Note
14.1.2 A Critical Look at SUBSANOs
14.2 Illustrative Demonstrations of the RL Species
14.2.1 Nanomaterials Growth on Solid Solution (Clustered) Islands
14.2.2 Nanomaterials Growth on Coarsened Substrates
14.2.3 Nanomaterials Growth on Metallic Substrates
14.2.4 Nanomaterials Growth on Nonmetallic Substrates
14.3 Nanomaterials Growths on Surfaces
14.3.1 Basics
14.3.2 Illustrations of SFSs
14.3.3 SFS Types and Defects Generation in These Types of SFSs
14.3.4 Heterointerfaces and Charge Transfers in SFSs
14.3.5 Influence of the Layer Thicknesses of Type-I and Type-II SFSs on Catalytic Activity
14.3.6 Influence of the Metallic SUBSANO Layer Thickness of Type-III SFSs on Catalytic Activity
14.4 High Catalytic Activities of Catalyst Surfaces
14.4.1 Key Catalyst Activities
14.4.2 Catalyst Surface Characteristics for Effective Catalytic Activities
14.4.3 Knudsen Diffusion, Interstitial Diffusion, and Substitutional Diffusion
14.4.4 Low-Temperature Decomposition of Gaseous Precursors
14.4.5 Is Catalyst Poisoning Real?
14.4.6 Catalyst Template Effects for Supersaturation
14.4.7 Membrane Template Effects
14.5 Conclusions
References
15 Simple Theoretical Model for Growth by the VQS Mechanism
15.1 Forwarding Note
15.2 FECA Nanoparticle Porosity for Nanowire Growths
15.3 FECA Nanoparticle Porosity for Nanotube Growths
15.4 Theoretical Models for Porosity, Pore Radius, and HET in Terms of Amorphicity
15.4.1 Surface Amorphicity
15.4.2 Pore Radius, Porosity, and HET Reactivity Defined in Terms of Effective Amorphicity
15.5 Knudsen Diffusivity
15.5.1 Formulation of Knudsen Diffusivity
15.5.2 Experimental Support for the Knudsen Diffusivity
15.6 Molecular and Knudsen Diffusion
15.7 Knudsen Permeability
15.8 Knudsen Diffusion Through Rough RL Species
15.9 Nanomaterial Growth Rate
15.10 Diffusivity and Permeability for Growths
15.10.1 Calculated Results for Diffusivity and Permeability
15.10.2 Surface Roughness Effects on Diffusivity
15.10.3 Surface Amorphicity Effects on Diffusivity
15.11 Carbon Nanotube Growth Rates
15.11.1 Variation of CNT growth rate with CNT diameter
15.11.2 Temperature-Dependent Variation of CNT Growth Rate
15.11.3 CNT Growth Rates Dependent on Growth Duration
15.11.4 CNT Growth Rates Dependent on Precursor Flow Rate
15.11.5 Inference
References
16 The General, Versatile Growth Mechanism
16.1 Generality of Growth Mechanism
16.1.1 Basics of Material Phases
16.1.2 Multiple Phases Participating in Nanomaterials Growths
16.1.3 General Pathway for Nanomaterials Growths
16.2 Important Hallmarks
16.2.1 Factors Influencing Nanomaterials Growths
16.2.2 Optimal Phase for SUBSANO-Mediated Growths
16.2.3 Optimal Phase for METANO-Mediated Growths
16.2.4 Uniqueness of the Nanoparticle Phase
16.2.5 Characteristics of SECINI Formed During Growths
16.3 Illustrations of Hallmarks
16.4 The VLS Mechanism is a Special Case of the VQS Mechanism
16.5 The VSS Mechanism, for Low-Temperature (T < TE) Growth, is a Special Case of the VQS Mechanism
16.5.1 Basics
16.5.2 Illustration with ZnO Nanowire Growths
16.5.3 Illustration with GaN and InN Nanowire Growths
16.5.4 Role of Intermediate Phases in Growths
16.5.5 Influence of Dopants, Contaminants and Stresses on Growths
16.5.6 Discrepancy in Growth Rates Explained
16.6 The VSS Mechanism, for High-Temperature (T > TE) Growth, is a Special Case of the VQS Mechanism
16.7 The VS Mechanism is a Special Case of the VQS Mechanism
16.7.1 Exceptional Roles of Surface Porosity and HETs in Growths
16.7.2 Exceptional Role of Surface Disorder in Growths
16.7.3 Exceptional Role of Oxygen Contaminants in Growths
16.7.4 The Role of Contaminant Assemblages in Growths
16.7.5 Impact of Substrate Scratching on Growths
16.8 Nanobelt Growth is by the VQS Mechanism, not by the VS or the VLS Mechanism
16.8.1 Preliminary Note
16.8.2 Nanobelt Synthesis and Conflicts and Contradictions in This Synthesis
16.8.3 Illustrative Demonstration of Nanobelts Being Growths by the VQS Mechanism
16.8.4 The RL Species Responsible for Nanobelt Growths
16.9 SFLS and SoLS Mechanisms Are the Special Cases of the VQS Mechanism
16.9.1 Catalyst-Mediated Si and Ge Nanowires Grown by the SFLS Mechanism
16.9.2 Catalyst-Free Si and Ge Nanowires Grown by the SFLS Mechanism
16.10 SLS Mechanism is a Special Case of the VQS Mechanism
16.10.1 Demonstration with Si Nanowire Growths
16.10.2 Demonstration with Indium Oxide Nanowire Growth
16.10.3 Demonstration with Silicon Nitride Nanowire Growths
16.10.4 Demonstration with Si Covered by a Layer of Ni
16.10.5 Inference
16.11 OAG Mechanism is a Special Case of the VQS Mechanism
16.12 SCG Mechanism is a Special Case of the VQS Mechanism
16.12.1 SCG Mechanism Based on Substrate Surface Disorder
16.12.2 SCG Mechanism Based on Substrate Surface Roughness
16.12.3 SCG Mechanism Based on Substrate Surface Porosity
16.12.4 Inferences
16.13 Boron Nitride Nanotube Growths Are by the VQS Mechanism
16.13.1 BNNTs and CNTs Compared
16.13.2 Key Features of BNNT Growths
16.13.3 BNNT Growths by Using Borazine
16.13.4 BNNT Growths by Using B–N–O Powder
16.13.5 BNNT Growths by Using Amorphous Boron
16.13.6 Effects of Processing Parameters on BNNT Growths
16.13.7 Effects of Laser Irradiation on BNNT Growths
16.14 Conclusions
16.14.1 Key Conclusions
16.14.2 Sticking of the Source Species and of the Precursors of the Source Species
16.14.3 Impact of Pressure on Nanoparticle Surface
16.14.4 Steps Involved in Growth Kinetics
16.14.5 Competitive Role of Temperature and Pressure During Growths
References
17 Conclusions
17.1 General Conclusions
17.2 Concerns About the VSS and the VS Mechanisms Reaffirmed
17.3 Concerns About Catalyst Droplets During Growths Affirmed
17.4 The Key Elements of the Book
17.5 Design Rules and Guidelines
References
Appendix A Effective Amorphicity of FECA Nanoparticle Surface
A.1 Introduction
A.2 The Role of the RS Species in Creating Effective Surface Amorphicity
A.2.1 What is effective surface amorphicity?
A.2.2 Nanopore radius
A.3 Novelty of Surface Amorphicity
Index