title: Few-electron edge-state quantum dots in a silicon nanowire field-effect transistor.
abstract: We investigate the gate-induced onset of few-electron regime through the undoped channel of a silicon nanowire field-effect transistor. By combining low-temperature transport measurements and self-consistent calculations, we reveal the formation of one-dimensional conduction modes localized at the two upper edges of the channel. Charge traps in the gate dielectric cause electron localization along these edge modes, creating elongated quantum dots with characteristic lengths of ∼10 nm. We observe single-electron tunneling across two such dots in parallel, specifically one in each channel edge. We identify the filling of these quantum dots with the first few electrons, measuring addition energies of a few tens of millielectron volts and level spacings of the order of 1 meV, which we ascribe to the valley orbit splitting. The total removal of valley degeneracy leaves only a 2-fold spin degeneracy, making edge quantum dots potentially promising candidates for silicon spin qubits.
authors.affiliation: SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC , 17 rue des Martyrs, 38054 Grenoble, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Voisin
authors.forename: Viet-Hung
authors.initials: VH
authors.lastname: Nguyen
authors.forename: Julien
authors.initials: J
authors.lastname: Renard
authors.forename: Xavier
authors.initials: X
authors.lastname: Jehl
authors.forename: Sylvain
authors.initials: S
authors.lastname: Barraud
authors.forename: François
authors.initials: F
authors.lastname: Triozon
authors.forename: Maud
authors.initials: M
authors.lastname: Vinet
authors.forename: Ivan
authors.initials: I
authors.lastname: Duchemin
authors.forename: Yann-Michel
authors.initials: YM
authors.lastname: Niquet
authors.forename: Silvano
authors.initials: S
authors.lastname: de Franceschi
authors.forename: Marc
authors.initials: M
authors.lastname: Sanquer