title: High mobility one- and two-dimensional electron systems in nanowire-based quantum heterostructures.
abstract: Free-standing semiconductor nanowires in combination with advanced gate-architectures hold an exceptional promise as miniaturized building blocks in future integrated circuits. However, semiconductor nanowires are often corrupted by an increased number of close-by surface states, which are detrimental with respect to their optical and electronic properties. This conceptual challenge hampers their potentials in high-speed electronics and therefore new concepts are needed in order to enhance carrier mobilities. We have introduced a novel type of core-shell nanowire heterostructures that incorporate modulation or remote doping and hence may lead to high-mobility electrons. We demonstrate the validity of such concepts using inelastic light scattering to study single modulation-doped GaAs/Al0.16Ga0.84As core-multishell nanowires grown on silicon. We conclude from a detailed experimental study and theoretical analysis of the observed spin and charge density fluctuations that one- and two-dimensional electron channels are formed in a GaAs coaxial quantum well spatially separated from the donor ions. A total carrier density of about 3 × 10(7) cm(-1) and an electron mobility in the order of 50,000 cm(2)/(V s) are estimated. Spatial mappings of individual GaAs/Al0.16Ga0.84As core-multishell nanowires show inhomogeneous properties along the wires probably related to structural defects. The first demonstration of such unambiguous 1D- and 2D-electron channels and the respective charge carrier properties in these advanced nanowire-based quantum heterostructures is the basis for various novel nanoelectronic and photonic devices.
authors.affiliation: Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, D-85748 Garching, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Funk
authors.forename: Miguel
authors.initials: M
authors.lastname: Royo
authors.forename: Ilaria
authors.initials: I
authors.lastname: Zardo
authors.forename: Daniel
authors.initials: D
authors.lastname: Rudolph
authors.forename: Stefanie
authors.initials: S
authors.lastname: Morkötter
authors.forename: Benedikt
authors.initials: B
authors.lastname: Mayer
authors.forename: Jonathan
authors.initials: J
authors.lastname: Becker
authors.forename: Alexander
authors.initials: A
authors.lastname: Bechtold
authors.forename: Sonja
authors.initials: S
authors.lastname: Matich
authors.forename: Markus
authors.initials: M
authors.lastname: Döblinger
authors.forename: Max
authors.initials: M
authors.lastname: Bichler
authors.forename: Gregor
authors.initials: G
authors.lastname: Koblmüller
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Finley
authors.forename: Andrea
authors.initials: A
authors.lastname: Bertoni
authors.forename: Guido
authors.initials: G
authors.lastname: Goldoni
authors.forename: Gerhard
authors.initials: G
authors.lastname: Abstreiter
mesh_terms: D001152:Arsenicals / Q000737:chemistry*; D003460:Crystallization; D004583:Electrons; D005708:Gallium / Q000737:chemistry*; D036103:Nanotechnology; D053770:Nanowires / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium; D012825:Silicon