Preferential nucleation, guiding, and blocking of self-propelled droplets by dislocations
Abstract
Lattice-mismatched layers of GaAs/InGaAs are grown on GaAs(001) using molecular beam epitaxy and subsequently heated in vacuum while the surface is imaged in situ using low-energy electron microscopy, in order to study (i) the nucleation of group-III droplets formed as a result of noncongruent sublimation and (ii) the dynamics of these self-propelled droplets as they navigate the surface. It is found that the interfacial misfit dislocation network not only influences the nucleation sites of droplets, but also exerts unusual steering power over their subsequent motion. Atypical droplet flow patterns including 90° and 180° turns are found. The directions of these dislocations-guided droplets are qualitatively explained in terms of in-plane and out-of-plane stress fields associated with the buried dislocations and the driving forces due to chemical potential and stress gradients typical of Marangoni flow. The findings would benefit processes and devices that employ droplets as catalysts or active structures such as droplet epitaxy of quantum nanostructures, vapor-liquid-solid growth of nanowires, or the fabrication of self-integrated circuits.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 19, 2018
- Source ID
- 10.1063/1.5008784
Entities
People
- Chalermchai Himwas
- Pat Photongkam
- Somsak Panyakeow
- Songphol Kanjanachuchai
- Suphakan Kijamnajsuk
- Thipusa Wongpinij
Organizations
- Air Force Office of Scientific Research
- Chulalongkorn University
- Thailand National Science and Technology Development Agency
- Thailand Research Fund