title: Gate-Tunable Spatial Modulation of Localized Plasmon Resonances.
abstract: We demonstrate localization and field-effect spatial control of the plasmon resonance in semiconductor nanostructures, using scattering-type scanning near-field optical microscopy in the mid-infrared region. We adopt InAs nanowires embedding a graded doping profile to modulate the free carrier density along the axial direction. Our near-field measurements have a spatial resolution of 20 nm and demonstrate the presence of a local resonant feature whose position can be controlled by a back-gate bias voltage. In the present implementation, field-effect induces a modulation of the free carrier density profile yielding a spatial shift of the plasmon resonance of the order of 100 nm. We discuss the relevance of our electrically tunable nanoplasmonic architectures in view of innovative optoelectronic devices concepts.
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Arcangeli
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Rossella
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Tomadin
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Jihua
authors.initials: J
authors.lastname: Xu
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Ercolani
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Sorba
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Beltram
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.|Dipartimento di Fisica, Università di Pisa , Largo Pontecorvo 3, I-56127 Pisa, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Tredicucci
authors.affiliation: Istituto Italiano di Tecnologia, Graphene Laboratories , Via Morego 30, I-16163 Genova, Italy.|NEST, Scuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Polini
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR , Piazza san Silvestro 12, I-56127 Pisa, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Roddaro
keywords: Plasmonics; doping engineering; field-effect; near-field optical microscopy; secmiconductor nanowire; sensors