title: Scaling hetero-epitaxy from layers to three-dimensional crystals.
abstract: Quantum structures made from epitaxial semiconductor layers have revolutionized our understanding of low-dimensional systems and are used for ultrafast transistors, semiconductor lasers, and detectors. Strain induced by different lattice parameters and thermal properties offers additional degrees of freedom for tailoring materials, but often at the expense of dislocation generation, wafer bowing, and cracks. We eliminated these drawbacks by fast, low-temperature epitaxial growth of Ge and SiGe crystals onto micrometer-scale tall pillars etched into Si(001) substrates. Faceted crystals were shown to be strain- and defect-free by x-ray diffraction, electron microscopy, and defect etching. They formed space-filling arrays up to tens of micrometers in height by a mechanism of self-limited lateral growth. The mechanism is explained by reduced surface diffusion and flux shielding by nearest-neighbor crystals.
authors.affiliation: Laboratory for Solid State Physics, ETH Zürich, Zürich, Switzerland. cfalub@phys.ethz.ch
authors.forename: Claudiu V
authors.initials: CV
authors.lastname: Falub
authors.forename: Hans
authors.initials: H
authors.lastname: von Känel
authors.forename: Fabio
authors.initials: F
authors.lastname: Isa
authors.forename: Roberto
authors.initials: R
authors.lastname: Bergamaschini
authors.forename: Anna
authors.initials: A
authors.lastname: Marzegalli
authors.forename: Daniel
authors.initials: D
authors.lastname: Chrastina
authors.forename: Giovanni
authors.initials: G
authors.lastname: Isella
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Müller
authors.forename: Philippe
authors.initials: P
authors.lastname: Niedermann
authors.forename: Leo
authors.initials: L
authors.lastname: Miglio