pH driven addressing of silicon nanowires onto Si3N4/SiO2 micro-patterned surfaces.
pH was used as the main driving parameter for specifically immobilizing silicon nanowires onto Si3N4 microsquares at the surface of a SiO2 substrate. Different pH values of the coating aqueous solution enabled to experimentally distribute nanowires between silicon nitride and silicon dioxide: at pH 3 nanowires were mainly anchored on Si3N4; they were evenly distributed between SiO2 and Si3N4 at pH 2.8; and they were mainly anchored on SiO2 at pH 2. A theoretical model based on DLVO theory and surface protonation/deprotonation equilibria was used to study how, in adequate pH conditions, Si nanowires could be anchored onto specific regions of a patterned Si3N4/SiO2 surface. Instead of using capillary forces, or hydrophilic/hydrophobic contrast between the two types of materials, the specificity of immobilization could rely on surface electric charge contrasts between Si3N4 and SiO2. This simple and generic method could be used for addressing a large diversity of nano-objects onto patterned substrates.
Université de Lyon, Institut des Nanotechnologies de Lyon, site Ecole Centrale de Lyon et site INSA de Lyon, France UMR 5270 CNRS, INSA de Lyon, ECL, UCBL, CPE, France. Laboratoire Nanotechnologies & Nanosystèmes, UMR 3463 CNRS, INSA de Lyon, ECL, UJF, Université de Sherbrooke, Pavillon P2-3IT, 3000 Boulevard de l'Université, Sherbrooke J1K 0A5, Québec, Canada.
Jean-Pierre
JP
Cloarec
Céline
C
Chevalier
Jonathan
J
Genest
Jacques
J
Beauvais
Hassan
H
Chamas
Yann
Y
Chevolot
Thierry
T
Baron
Abdelkader
A
Souifi