Strain-driven mesoscopic reconstruction of the As/Ge(111) surface
W E McMahon1, Iskander G Batyrev, J M Olson
1National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, USA.
Physical Review Letters
|August 23, 2002
Summary
Large hexagonal tiles on As/Ge(111) surfaces form trenches with a (5-7-5)-ringed structure. This mesoscopic reconstruction is driven by surface strain relaxation, as confirmed by experiments and calculations.
Area of Science:
- Surface science
- Materials science
- Condensed matter physics
Background:
- Arsenic (As) and Germanium (Ge) surfaces exhibit complex reconstructions.
- Understanding surface structures is crucial for semiconductor device fabrication.
Purpose of the Study:
- To elucidate the structure of trenches on As/Ge(111) surfaces.
- To investigate the driving forces behind the observed mesoscopic reconstruction.
Main Methods:
- Scanning tunneling microscopy (STM) for surface imaging.
- First-principles total energy calculations for atomic-level simulations.
- Continuum elasticity theory for macroscopic analysis.
Main Results:
- Observation of periodic arrays of large hexagonal tiles (up to 170 Å).
- Identification of a (5-7-5)-ringed structure in the trenches between tiles.
- Confirmation that trench formation is an exothermic process.
- Agreement between calculated and experimental trench spacing (~104 Å).
Conclusions:
- The mesoscopic reconstruction of As/Ge(111) surfaces is primarily driven by long-range surface strain relaxation.
- First-principles calculations and continuum elasticity theory provide consistent explanations for the observed phenomena.
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