Fundamental Properties of Semiconductor Nanowires

Preface
Contents
Growth
Vapor–Liquid–Solid Growth of Semiconductor Nanowires
	1 Introduction
	2 Vapor–Liquid–Solid Growth of Semiconductor Nanowires
	3 Basics of the Nanowire Growth Modeling
	4 Role of Surface Energy
	5 Selective Area Epitaxy of III–V Nanowires
	6 Growth Kinetics of III–V Nanowires
		6.1 Transport-Limited Nanowire Growth
		6.2 Chemical Potentials for the VLS Growth of III–V Nanowires
		6.3 Nucleation and Growth of 2D Islands
		6.4 Self-Consistent Growth Models
	7 Self-equilibration of the Radius of Self-catalyzed Nanowires
	8 Length Distributions of Nanowires
	9 Semiconductor Alloys in Nanowires
		9.1 Introduction
		9.2 Description of the Vapor, Liquid and Solid Phases
		9.3 Dependence of Alloy Composition on Vapor Fluxes
		9.4 Dependence of Solid Composition upon Liquid Composition
	10 Heterostructures in Nanowires
		10.1 Elastic and Plastic Strain Relaxation in Axial Heterostructures—Critical Dimensions
		10.2 VLS Growth of Axial Heterostructures
		10.3 Modeling the Formation of Axial Heterostructures
	11 Polytypism
		11.1 Introduction
		11.2 Models
		11.3 Crystal Phase Heterostructures
	References
Functionalization
Surface Functionalization of III–V Nanowires
	1 Introduction
	2 Fundamentals of III–V Nanowire Surface Structure and Morphology
	3 Methods for Surface Characterization; STM, XPS, PEEM
	4 Initial Formation and Control of the Clean Crystalline NW Surface
	5 Surface Functionalization and Electronic Properties: Native Oxide Versus High-k Dielectric Layer
	6 Enhancing Nanowire Functionality via Surface Functionalization
	References
Impurity Doping in Semiconductor Nanowires
	1 Introduction
	2 Doping Methods
		2.1 Ex Situ Doping
		2.2 In Situ Doping
		2.3 Molecular Doping (Surface Transfer Doping)
	3 Characterization of Impurity Doping
		3.1 Electrical Analysis
		3.2 Optical Analysis
		3.3 Spin Analysis
		3.4 Probe Analysis
		3.5 Mass Analysis
	4 Behaviors of Dopant Atoms
	5 Summary and Conclusion
	References
Characterization
X-ray Methods for Structural Characterization of III-V Nanowires: From an ex-situ Ensemble Average to Time-resolved Nano-diffraction
	1 Introduction
		1.1 Motivation
		1.2 GaAs Crystal Structure
		1.3 X-Ray Diffraction of GaAs Nanostructures
		1.4 X-Ray Diffraction Geometry for in-situ 3D reciprocal space mapping
	2 in-situ X-ray Diffraction of Nanowire Ensembles During Growth
		2.1 Experimental Requirements
		2.2 Evolution of Polytypism in GaAs Nanowires
		2.3 Radial Growth of GaAs Nanowires and Shape Evolution of Liquid Ga-Droplet
		2.4 in-situ X-ray diffraction of GaAs-(In,Ga)As core-shell nanowires during growth
	3 Outlook
		3.1 in-situ X-ray diffraction of individual nanowires
		3.2 in-situ X-ray diffraction of small ensembles defined by substrate patterning
	References
Characterisation of Semiconductor Nanowires by Electron Beam Induced Microscopy and Cathodoluminescence
	1 Electron Beam/Matter Interaction
	2 Electron Beam Induced Current Mapping
		2.1 Measurement Configurations
		2.2 EBIC Applied to the Analysis of NW Properties
	3 Cathodololuminescence
		3.1 SEM-CL Mapping Applied to Nanowires
		3.2 TR-CL Analysis Applied to Nanowires
	4 Conclusions
	References
Photoluminescence Spectroscopy Applied to Semiconducting Nanowires: A Valuable Probe for Assessing Lattice Defects, Crystal Structures, and Carriers’ Temperature
	1 Introduction
	2 Low-temperature Photoluminescence
		2.1 Samples
		2.2 Impurity States
	3 Optical Selection Rules in Wurtzite Crystals
	4 Temperature-Dependent Studies
		4.1 Temperature Dependence of Optical Transitions in Wurtzite Nanowires
		4.2 Thermal Budget Management in NWs
	5 Conclusions
	References
Addressing Crystal Structure in Semiconductor Nanowires by Polarized Raman Spectroscopy
	1 Introduction
		1.1 Crystal Structures of Nanowires
		1.2 Crystal Symmetry and Phonon Dispersion
	2 Polarized Raman Scattering: Fundamental Aspects and Selection Rules
		2.1 Theoretical Description of Inelastic Light Scattering
		2.2 Raman Cross Section and Raman Tensors: Selection Rules
		2.3 Experimental Setup and Scattering Geometry
		2.4 Relaxation of Selection Rules
	3 Polarized Raman Scattering: Phononic and Crystalline Properties of Nanowires
		3.1 Cubic Monoatomic Crystals
		3.2 Hexagonal Monoatomic Crystals
		3.3 Polytypic Homostructures in Nanowires
	4 Electronic Properties of Nanowires: Resonant Raman
		4.1 Resonant Raman Studies as a Probe of Electronic Transitions
		4.2 Probing Critical Points of Electronic Bands
		4.3 Unveiling Band Alignment in Heterostructures
	5 Conclusions
	References
Theoretical Aspects of Point Defects in Semiconductor Nanowires
	1 Introduction
	2 Fundamentals
		2.1 Excitation Energies Versus Transition Levels
		2.2 Formation Energy
		2.3 Chemical Potential
		2.4 Charged Defects
		2.5 Computational Aspects
	3 Defects in Nanowires
		3.1 Chemical Potentials
		3.2 Madelung Energies for Anisotropic Materials and Dielectric Screening
		3.3 Al Substitutional in a Thin SiNW
	4 Conclusions
	References
Applications
Nanowire Field-Effect Transistors
	1 Introduction
	2 Basics of NW-FETs
		2.1 Issues and Requirements for FETs in Modern Electronics
		2.2 Short Channel Effect in NW-FETs
		2.3 Modeling of NW-FETs
		2.4 Advantages of Vertical NW-FETs with Bottom-Up NWs
	3 Fabrication of Nanowire Vertical FETs
		3.1 Nanowire Growth
		3.2 Fabrication of Vertical NW-FETs
	4 Current Status of NW-FETs
		4.1 Static Characteristics
		4.2 High-Frequency Characteristics
		4.3 Utilization of Heterostructures
	5 Enhancement of Functionality of Vertical NW-FETs
		5.1 Tunnel Field-Effect Transistors
		5.2 p-Channel FETs and CMOS Structure
		5.3 Spin-FETs
		5.4 GaN-Based Vertical NW-FETs
	6 Summary
	References
InP/InAs Quantum Heterostructure Nanowires Toward Telecom-Band Nanowire Lasers
	1 Introduction
	2 InP and InAs Nanowires Grown by Self-Catalyzed VLS Mode
	3 InP/InAs Heterostructure Nanowires by Self-Catalyzed VLS Mode
	4 Telecom-Band Lasing in Single InP/InAs Nanowires
	5 Site Control of InP/InAs Heterostructure Nanowires
	6 In Situ Tuning Nanowire Diameter
	7 Summary
	References