Heterogeneous nucleation of coherently strained islands during epitaxial growth of Ge on Si(110)

Abstract

We report on the molecular beam epitaxial growth of Ge on Si(110) surfaces. High temperature cleaning (oxide desorption) results in the formation of shallow faceted pits distributed randomly on the Si(110) surface. Deposition of Ge at temperatures between 600 and 725 °C leads to preferential nucleation along the pit edges forming elongated islands, which subsequently grow to compact three-dimensional coherent islands. The observation of strained islands in close proximity to each other offers insights into their nucleation behavior and strain relaxation. Our observations suggest heterogeneous nucleation as a possible method for fabricating assemblies of quantum dots.