Essence of intermediate oxide layer

For more info about our services contact : help@bestpfe.com

Table of contents

Table of contents
General Introduction
Organization of this thesis
Chapter 1: Necessity for a novel substrate for gallium nitride nanowires
1.1 Gallium Nitride: An introduction
1.1.1 A brief history of GaN crystal growth
1.1.2 Substrates for epitaxial growth of GaN
1.2 Introduction to Nanowires
1.2.1 Advantages of nanowires
1.2.2 NW growth by PAMBE
1.3 Novel substrates for GaN NWs
1.3.1 Motivation
1.3.2 State of the art: NW growth on non-conventional substrates
1.3.3 Objective of this project
References
Chapter 2: Conventional gallium nitride nanowires growth on Si(111) bulk substrate
2.1 Introduction and state-of-the-art
2.1.1 Brief introduction
2.1.2 State-of-the-art
2.2 Standard growth conditions and results
2.2.1 Substrate preparation
2.2.2 Substrate temperature calibration
2.2.3 Flux calibration
2.2.4 Aluminium Nitride pre-deposition
2.2.5 GaN NW growth
2.2.6 Characterisation of GaN NWs
2.2.6.1 Morphology of the NWs
2.2.6.2 Pole-figure measurements
2.2.6.3 Polarity of the NWs
2.2.6.4 Photoluminescence measurements
2.3 Summary
References
Chapter 3: AIC-Si as a substrate for gallium nitride nanowire growth
3.1 Introduction and objective
3.1.1 Means of obtaining thin polycrystalline-Si layers
3.1.2 Aluminium induced crystallization of Si (AIC-Si)
3.1.3 Potential substrate for NW growth
3.1.3.1 Fiber texture
3.1.3.2 Proof of concept for GaAs NWs
3.1.4 State of the art: AIC layers as substrate for NW epitaxy
3.1.4.1 Growth of Ge nanowires on AIC-Ge substrates
3.1.4.2 Growth of Si nanowires on AIC-Si substrate
3.1.4.3 High density GaAs NWs on AIC-Si
3.1.5 Objective of this work
3.2 Synthesis of AIC-Si
3.2.1 Thermodynamics of AIC-Si formation
3.2.1.1 Al/Si ratio
3.2.1.2 Annealing process
3.2.1.3 Essence of intermediate oxide layer
3.2.2 Preparation and optimisation of thin Si layers
3.2.2.1 Experimental section
3.2.2.1.1 Deposition of the layers
3.2.2.1.2 Crystallisation and surface treatment
3.2.2.2 Optimisation of the layer
3.2.2.2.1 Possible minimum thickness for continuous c-Si layer
3.2.2.1.2 Surface roughness and fiber-texture quality
3.3 GaN nanowires on AIC-Si
3.3.1 Growth of GaN nanowires on continuous AIC-Si layers
3.3.2 Characterisation of the NWs
3.3.2.1 Verticality of NWs
3.3.2.2 Polarity of NWs
3.3.3 Surface deformation
3.4 Growth on patterned AIC-Si
3.4.1 Preliminary results for selective growth
3.4.2 Fabrication of AIC-Si nano-islands by lithography
3.4.2 Vertical GaN NWs on AIC-Si nano-islands
3.5 Conclusion and future scope
References
Chapter 4: Gallium nitride nanowires on silica
4.1 Introduction and objectives
4.1.1 Amorphous Substrates
4.1.2 Objective
4.2 State of the art: Silica substrate
4.3 GaN nanowires on silica
4.3.1 Thermal and fused silica substrates preparation
4.3.2 Growth of GaN NWs
4.3.3 Growth evolution
4.4 Characterisation
4.4.1 Structural quality
4.4.1.1 Verticality
4.4.1.2 TEM analysis
4.4.1.3 Polarity
4.4.1.4 Bushes
4.4.2 Optical quality
Conclusion and future scope
References
Chapter 5: Gallium nitride nanowires on graphene
5.1 Introduction and objectives
5.1.1 A brief introduction to graphene
5.1.2 Van der Waals epitaxy
5.1.3 State of the art: Graphitic substrates
5.1.4 Objective
5.2 GaN nanowires on graphene
5.2.1 Different type of graphene layers
5.2.1.1 Preparation of graphene patch samples
5.2.1.2 Preparation of graphene flake samples
5.2.2 Growth of GaN NWs
5.2.2.1 On graphene monolayer patch
5.2.2.2 On graphene flakes
5.2.2.3 Silica intermediate layer
5.3 Characterisation
5.3.1 XRD and Pole-figure results
5.3.3 TEM results
5.3.4 Photoluminescence results
5.4 Epitaxial growth of GaN on graphene
5.4.1 Lattice relationship with graphene
5.4.1.1 SEM observation
5.4.1.2 SAED patterns
5.4.2 Epitaxial growth configuration
5.4.3 Difference in NW nucleation with respect to different number of MLs of graphene*
5.5 Proof of concept for selective area growth of NWs on graphene
5.5.1 Patterning process of graphene
5.5.2 Growth on micro- and nano- patches of graphene ML
5.6 Conclusion and future scope
References
Conclusion
Appendix
A.1 Crystal properties of GaN
A.2 Defects and dislocations in GaN
A.3 Plasma assisted molecular beam epitaxy (PAMBE)
A.4 Reflective high energy electron diffraction (RHEED)
A.5 X-ray diffraction (XRD)
A.6 Photoluminescence
References