Elastic Interactions in Epitaxial Growth A Qualifier Proposal

1
Elastic Interactions in Epitaxial GrowthA
Qualifier Proposal

• Bruno Miguel Tavares Gonçalves

2
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

3
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

4
Objectives

• Reproduce experimental results
• Extend the results previously obtained
• Improve our understanding of MBE phenomena that
  results in the formation of quantum dots (QD)
• Pin point the most relevant aspects of the QD
  formation process
• To create a realistic, physically correct and
  computationally efficient simulation!

5
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

6
Molecular Beam Epitaxy
7
Growth Modes
8
Experimental Results

• Similar sizes and shapes independent of the
  coverage
• Can be used to create QD

9
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

10
Elastic Interaction (1)
11
Elastic Interaction (2)
12
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

13
Monte-Carlo Method

• Generate a new system configuration
• Calculate the energy difference between the new
  and the current configuration
• Change the state of the system with probability

14
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

15
Ehrlich-Schwoebel Barrier
16
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

17
Material Properties (1)
18
Material Properties (2)
19
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

20
Algorithm
Select Location
No
Yes
Yes
No
21
Parallelization
22
Contents

• Objectives
• Molecular Beam Epitaxy
• Elastic Interaction
• Monte-Carlo Method
• Ehrlich-Schwoebel Barrier
• Material Properties
• Simulation
• Discussion

23
Final Remarks (1)

• Succesful simulation would allow us to
• Confirm the theoretical picture
• Identify the relative importance of the different
  physical processes
• Overcome experimental observational difficulties
• Visualize in considerable detail the systems
  evolution
• Improve our understanding of the system

24
(No Transcript)
25
Final Remarks (3)

• If the simulation proves incapable of reproducing
  the experimental results
• Suggest revisions to the underlying assumptions
• Suggest modifications to theoretical ideas
• Identify gaps in our understanding of the system
• Contribute to correcting those gaps

26
The End