resumo
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.
palavras-chave
NANOCRYSTAL SUPERLATTICES; COLLOIDAL NANOCRYSTALS; GOLD NANOPARTICLES; SURFACE LIGANDS; ELECTROMIGRATION; FABRICATION; ELECTRODES
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Yu, Q; Cui, LM; Lequeux, N; Zimmers, A; Ulysse, C; Rebuttini, V; Pinna, N; Aubin, H
nossos autores
Nicola Pinna
InvestigadorGrupos
agradecimentos
We acknowledge support from ANR grant