Thermal Stability of Strained Nanowires

TL;DR

This paper theoretically investigates the thermal stability of strained nanowires, revealing phase transitions and coexistence regions influenced by temperature and height, and explains recent experimental data on erbium silicide growth.

Contribution

It introduces a thermodynamic model for nanowire stability considering thermal fluctuations, extending beyond previous simple energetic models.

Findings

Phase transitions from nanowires to nanoislands with temperature changes

Identification of regions of phase coexistence

Explanation of recent experimental observations on erbium silicide growth

Abstract

Stranski-Krastanov strained islands undergo a shape anisotropy transition as they grow in size, finally evolving toward nanowires. This effect has been explained until now via simple energetic models that neglect thermodynamics. We investigate theoretically the stability of strained nanowires under thermal fluctuations of the long side. We find phase transitions from nanowires back to nanoislands as the temperature is increased and as the height of the nanostructure is raised or lowered and we predict regions of phase coexistence. Our results are general, but explain recent data on the growth of erbium silicide on a vicinal Si surface.