title: Controlling the reproducibility of Coulomb blockade phenomena for gold nanoparticles on an organic monolayer/silicon system.
abstract: Two types of highly ordered organic layers were prepared on silicon modified with an amine termination for binding gold nanoparticles (AuNPs). These two grafted organic monolayers (GOMs), consisting of alkyl chains with seven or 11 carbon atoms, were grafted on oxide-free Si(111) surfaces as tunnel barriers between the silicon electrode and the AuNPs. Three kinds of colloidal AuNPs were prepared by reducing HAuCl4 with three different reactants: citrate (Turkevich synthesis, diameter ∼16 nm), ascorbic acid (diameter ∼9 nm), or NaBH4 (Natan synthesis, diameter ∼7 nm). Scanning tunnel spectroscopy (STS) was performed in a UHV STM at 40 K, and Coulomb blockade behaviour was observed. The reproducibility of the Coulomb behavior was analysed as a function of several chemical and physical parameters: size, crystallinity of the AuNPs, influence of surrounding surfactant molecules, and quality of the GOM/Si interface (degree of oxidation after the full processing). Samples were characterized with scanning tunneling microscope, STS, atomic force microscope, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy (XPS), and high resolution transmission electronic microscope. We show that the reproducibility in observing Coulomb behavior can be as high as ∼80% with the Natan synthesis of AuNPs and GOMs with short alkyl chains.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7588, Institut des NanoSciences de Paris, 4 place Jussieu, F-75005 Paris, France. Laboratory for Surface and Nanostructure Modifications, Department of Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Dallas, Texas 7508, USA.
authors.forename: L
authors.initials: L
authors.lastname: Caillard
authors.forename: S
authors.initials: S
authors.lastname: Sattayaporn
authors.forename: A-F
authors.initials: AF
authors.lastname: Lamic-Humblot
authors.forename: S
authors.initials: S
authors.lastname: Casale
authors.forename: P
authors.initials: P
authors.lastname: Campbell
authors.forename: Y J
authors.initials: YJ
authors.lastname: Chabal
authors.forename: O
authors.initials: O
authors.lastname: Pluchery