Block copolymer mediated deposition of metal nanoparticles on germanium nanowires
Department of Chemistry, University of Alberta, Edmonton, Alberta, CanadaChemical Communications (Impact Factor: 6.72). 04/2007; DOI: 10.1039/b616883c
ABSTRACT Galvanic displacement, mediated by a diblock copolymer, leads to deposition of well dispersed gold and silver nanoparticles on germanium nanowires.
[Show abstract] [Hide abstract]
ABSTRACT: Colloidal hybrid nanoparticles, which contain multiple inorganic domains that are joined together through solid–solid interfaces, exhibit particle multifunctionality as well as new and enhanced properties that can emerge from the particle–particle interactions. These hybrid nanoparticles are typically synthesized using heterogeneous seeded nucleation of one nanoparticle on the surface of another as well as using phase segregation, surface dewetting of core–shell nanoparticles, and the fusion of premade nanoparticles. However, to expand the materials diversity and the potential range of applications of such systems, alternative routes to heterogeneous seeded nucleation are needed. Here, we show that solution–liquid–solid and related supersaturation-precipitation strategies, traditionally used in the synthesis of 1D structures such as nanowires and nanorods, can also be applied to the synthesis of colloidal hybrid nanoparticles. Specifically, we show that colloidal Au and Ag nanoparticles can serve as seeds for the growth of colloidal Au–Ge and Ag–Ge heterodimers upon reaction with Ge(HMDS)2 (Ge(II)bis(hexamethyldisilylamide)) at 290 and 320 °C, respectively. By modifying the size of the seed nanoparticles and the amount of Ge(HMDS)2, the widths and lengths of the Ge domains can be systematically tuned. Additionally, the Ge domains can serve as site-selective templates for the galvanic deposition of metal nanoparticles, forming trimeric Au–Ge–(Ag)n nanostructures. This alternate route to colloidal hybrid nanoparticles facilitates the integration of previously inaccessible group IV elements, and it could open the door to the design and synthesis of a wide range of new functional colloidal nanostructures.Chemistry of Materials 10/2013; 25(21):4304–4311. DOI:10.1021/cm4024452 · 8.54 Impact Factor
Advanced Materials 12/2008; 20(24):4789-4792. DOI:10.1002/adma.200703233 · 15.41 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Electroless silver deposition (for 1–100s) has been simultaneously performed on (100) and (111) planes of macro and micro patterned silicon, fabricated using optical lithography and anisotropic etching with alkaline solution. Metal clusters formation occurs preferentially on the upper edge region separating the two main planes. Their density and mean size are higher on the (100) plane. Similar experiments performed on same patterned samples but with the surface amorphized by ion implantation elucidated the role played by the preferential mass transport caused by the pattern geometry. For the micro-sized pyramidal holes, the non uniform surface distribution of metal clusters is enhanced. The metal deposition occurs mainly on the (100) top strips surrounding the pyramids. The subsequent preferential oxidation of silicon under the metallic clusters gives rise to nanowires of (100) and (111) orientation in the macro and to nanopillars in the micro patterns respectively. Nanowire's tips are preferentially sites for metal deposition as shown after re-immersion in the plating solution. Samples with contiguous one dimensional nanostructures of different orientation could be used for the study of transport properties’ anisotropy. The formation of metal tips on top of the nanostructures might be of relevance in the field of metal-semiconductor contacts.Journal of The Electrochemical Society 08/2013; 2(9):405-414. DOI:10.1149/2.002311jss · 2.86 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.