title: Monolithic growth of ultrathin Ge nanowires on Si(001).
abstract: Self-assembled Ge wires with a height of only 3 unit cells and a length of up to 2 micrometers were grown on Si(001) by means of a catalyst-free method based on molecular beam epitaxy. The wires grow horizontally along either the [100] or the [010] direction. On atomically flat surfaces, they exhibit a highly uniform, triangular cross section. A simple thermodynamic model accounts for the existence of a preferential base width for longitudinal expansion, in quantitative agreement with the experimental findings. Despite the absence of intentional doping, the first transistor-type devices made from single wires show low-resistive electrical contacts and single-hole transport at sub-Kelvin temperatures. In view of their exceptionally small and self-defined cross section, these Ge wires hold promise for the realization of hole systems with exotic properties and provide a new development route for silicon-based nanoelectronics.
authors.affiliation: Institute for Integrative Nanosciences, IFW Dresden, D-01069 Dresden, Germany. j.zhang@ifw-dresden.de
authors.forename: J J
authors.initials: JJ
authors.lastname: Zhang
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authors.lastname: Katsaros
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authors.lastname: Montalenti
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authors.lastname: Mickel
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authors.lastname: Rellinghaus
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authors.lastname: Miglio
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authors.initials: S
authors.lastname: De Franceschi
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authors.lastname: Rastelli
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authors.lastname: Schmidt