Crystal Structure Transfer in Core/Shell Nanowires

• Published in: Nano letters 2011-04, Vol.11 (4), p.1690-1694
• Main Authors: Algra, Rienk E, Hocevar, Moïra, Verheijen, Marcel A, Zardo, Ilaria, Immink, George G. W, van Enckevort, Willem J. P, Abstreiter, Gerhard, Kouwenhoven, Leo P, Vlieg, Elias, Bakkers, Erik P. A. M
• Format: Article
• Language: English
• Subjects: Condensed Matter; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallization - methods; Exact sciences and technology; Macromolecular Substances - chemistry; Materials Science; Materials Testing; Molecular Conformation; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotubes; Particle Size; Physics; Quantum wires; Silicon - chemistry; Structure of solids and liquids; crystallography; Surface Properties
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl200208q

Structure engineering is an emerging tool to control opto-electronic properties of semiconductors. Recently, control of crystal structure and the formation of a twinning superlattice have been shown for III−V nanowires. This level of control has not been obtained for Si nanowires, the most relevant material for the semiconductor industry. Here, we present an approach, in which a designed twinning superlattice with the zinc blende crystal structure or the wurtzite crystal structure is transferred from a gallium phosphide core wire to an epitaxially grown silicon shell. These materials have a difference in lattice constants of only 0.4%, which allows for structure transfer without introducing extra defects. The twinning superlattices, periodicity, and shell thickness can be tuned with great precision. Arrays of free-standing Si nanotubes are obtained by a selective wet-chemical etch of the core wire.