Forbidden island heights in stress-driven coherent Stranski-Krastanov growth

Abstract

The observed height distribution of clusters obtained in strained epitaxy has been often interpreted in terms of electronic effects. We show that some aspects can be explained classically by the interplay of strain and edge energies. We find that soft materials can transform directly from monolayer into thicker islands by two-dimensional (2D) multilayer nucleation and growth. There is a critical thickness decreasing with the force constant. Thinner islands are thermodynamically forbidden, due to the insufficient stress relaxation upon clustering particularly under tensile stress. At sufficiently large misfits the barrier for 2D multilayer nucleation is significantly smaller than the barrier for subsequent single-layer nucleation. The effects are found to be quantitatively reasonable and offer a plausible explanation for the absence of thin islands and 2D growth of flattop islands usually attributed to quantum size effects.

4 pages, 4 figures. Accepted version. Includes quantitative estimations comparing with experiments plus minor changes

References in corpus (4)

• Quantum size effects in the low temperature layer-by-layer growth of Pb on Ge(001)
• Thermodynamic driving force of formation of coherent three-dimensional islands in Stranski-Krastanov growth
• Quantum-dot nucleation in strained-layer epitaxy: minimum-energy pathway in the stress-driven 2D-3D transformation
• From bi-layer to tri-layer Fe nanoislands on Cu3Au(001)

Cited by in corpus (4)

• Stranski-Krastanov mechanism of growth and the effect of misfit sign on quantum dots nucleation
• Influence of the substrate lattice structure on the formation of Quantum Well States in thin In and Pb films on silicon
• Second-layer nucleation in coherent Stranski-Krastanov growth of quantum dots
• Effect of the lattice misfit on the equilibrium shape of strained islands in Volmer-Weber growth