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S. Barth:
"Metal-Assisted Growth of Germanium Nanowires: Opportunities using Solid Metal Seed";
Talk: 4^th EuCheMS Chemistry Congress, Prague, Czech Republic; 2012-08-26 - 2012-08-30; in: "4^th EuCheMS Chemistry Congress - Final Program", (2012), O-519.

One-dimensional (1D) semiconductor nano-architectures with tunable morphologies, dimensions, crystallographic phases and orientation are of tremendous interest for a broad range of applications. Metal-seeded growth of 1D semiconductor nanostructures is still a very active field of research, despite the huge progress which has been made in understanding this fundamental phenomenon. Liquid growth promoters allow control of the aspect ratio, diameter and structure of 1D crystals via external parameters, such as precursor feedstock, temperature and operating pressure. However the transfer of crystallographic information from a nanoparticle seed to a growing nanowire has not been described in the literature. We investigated the formation of Ge nanowires using solid metal growth promoters in a process based on thermal decomposition of diphenylgermane. The theoretical requirements for transferring information such as defects from nanoparticle seeds to growing semiconductor nanowires have been defined and we describe why specific metal nanoparticles are ideal candidates for this purpose. Significantly, under certain reaction conditions {111} stacking faults in the noble metal seeds can be directly transferred to a high percentage of <112>-oriented Ge nanowires, in the form of radial twins in the semiconductor crystals. In addition, we will detail the influence of solid growth seeds on the crystal quality of Ge nanowires and demonstrate size-selective growth in the sub-20 nm diameter regime. Controlled defect transfer from nanoparticles to nanowires could open up the possibility of engineering 1D nanostructures with new and tuneable physical properties and morphologies.

Crystal growth; Chemical vapor deposition; Nanostructures; Electron diffraction