Abstract :

The implementation of nanowires and nanotubes for applications such as thermoelectrics, catalysis, plasmonics, or photoelectrochemical water splitting for hydrogen generation requires both, an excellent control on geometry, crystallinity and composition of the individual nanostructures, as well as its successful assembly into 2-D and 3-D architectures. This talk will illustrate how the unique combination of electrodeposition and tailored nanochannel templates provides an excellent platform (i) to study and control the nanowire growth, (ii) to investigate their size-dependent properties, and (iii) to develop 3D and multicomponent nanostructure assemblies. Membranes with parallel nanochannels are fabricated by swift heavy ion irradiation and subsequent chemical etching. In addition, templates with interconnected tilted nanochannels are obtained by applying ion irradiation at several incident angles in consecutive steps. Nanochannel density and orientation, as well as diameter and geometry, are adjusted by the irradiation and etching conditions, respectively. [1] Subsequent electrodeposition in the channels results in nanowire arrays and highly ordered 3-D nanowire ensembles of various materials. Recent developments achieved on the electrodeposition of metal (Au1-xAgx) [2,3], semiconductor (ZnO and p-Cu2O) [4] and semimetal (Sb) nanowire arrays and nanowire networks [5] will also be presented.

[1] Characterization and properties of micro- and nanowires of controlled size, composition, and geometry fabricated by electrodeposition and ion-track technology, M.E. Toimil-Molares, Beilstein J. Nanotechnol. 3 (2012) 860-883.
[2] Visualization of Multipolar Longitudinal and Transversal Surface Plasmon Modes in Nanowire Dimers, I. Alber, W. Sigle, S. Müller, R. Neumann, O. Picht, M. Rauber, P. A. van Aken, M.E. Toimil-Molares, ACS Nano, 5 (12) (2011) 9845-9853.
[3] Surface enrichment in Au–Ag alloy nanowires and investigation of the dealloying process, L. Burr, I. Schubert, W. Sigle, C. Trautmann, M.E. Toimil-Molares, J. Phys. Chem. C 119 (2015) 20949-20956.
[4] ZnO Nanowire Networks as Photoanode Model Systems for Photoelectrochemical Applications, L. Movsesyan, A.W. Maijenburg, N. Goethals, W. Sigle, A. Spende, F. Yang, B. Kaiser, W. Jaegermann, S.-Y. Park, G. Mul, C. Trautmann, M.E. Toimil-Molares, Nanomaterials (2018) 8, 693.