title: In-vacuum projection of nanoparticles for on-chip tunneling spectroscopy.
abstract: Starting with a discussion of the percolation problem applied to the trapping of conducting nanoparticles between nanometer-spaced electrodes, we show that a good strategy to trap a single nanoparticle between the electrodes is to prepare chips with low coverage of nanoparticles to avoid percolating current paths. To increase the probability of trapping a single nanoparticle, we developed a new method where nanoparticles are projected in-vacuum on the chip, followed by a measure of the tunnel current, in a cycle that is repeated up to a few thousand times until a preset threshold value is reached. A plot of the tunneling current as a function of time allows discriminating between the two possible current paths, i.e., a single nanoparticle trapped between the electrodes or a percolating path across many nanoparticles. We applied the method to prepare chip circuits with single gold nanoparticles, as demonstrated by the observation of Coulomb blockade. Furthermore, we applied the method to trap single magnetite nanoparticles for the study of electric-field-induced switching from insulator to metal in single nanoparticles.
authors: Laboratoire de Physique et d'Etude des Matériaux, UMR 8213, ESPCI-ParisTech-CNRS-UPMC, 10 Rue Vauquelin, 75231 Paris, France.
authors: Qian
authors: Q
authors: Yu
authors: Limin
authors: L
authors: Cui
authors: Nicolas
authors: N
authors: Lequeux
authors: Alexandra
authors: A
authors: Zimmers
authors: Christian
authors: C
authors: Ulysse
authors: Valentina
authors: V
authors: Rebuttini
authors: Nicola
authors: N
authors: Pinna
authors: Hervé
authors: H
authors: Aubin