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Fast coarsening in unstable epitaxy with desorption
1Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 53 Prague 6, Czech Republic.
Summary
Homoepitaxial growth instability leads to pyramidal mounds. Adding desorption accelerates mound coarsening, with larger mounds growing faster due to reduced evaporation.
Area of Science:
- Materials Science
- Surface Physics
- Computational Modeling
Background:
- Homoepitaxial growth can become unstable, forming pyramidal mounds.
- Instability arises from reduced interlayer transport due to step-edge hopping barriers.
Purpose of the Study:
- To investigate the effect of desorption on mound array coarsening during homoepitaxial growth.
- To understand the underlying mechanisms driving accelerated coarsening.
Main Methods:
- Simulations using a lattice model.
- Analysis with a continuum equation.
Main Results:
- A small amount of desorption significantly speeds up mound array coarsening.
- Observed coarsening exponents fall between 1/3 and 1/2.
- Larger mounds exhibit faster growth due to lower evaporation rates.
Conclusions:
- Desorption is a critical factor in controlling mound coarsening kinetics.
- The model explains the observed acceleration and growth dynamics of larger mounds.