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Semiconductor nanowires grown by the Vapor-Liquid-Solid mechanism are playing a dominant role on the development of novel nanoelectronic, nanooptical and nanoelectromechanical systems. Different growth methods have been explored so far, most relying on the use of metal nanoparticles as catalyst for the nanowire synthesis. It has also been demonstrated that by manipulating the size and location of the metal nanoparticles it is possible to control the diameter and position of the nanowires. Though several approaches to follow such strategy have been proposed, nanowire growth with very precise control of their position and reduced diameter distribution still remains a challenge. In this contribution we describe a metal catalyst nanoparticle deposition method based on a galvanic displacement (GD) process from reversed micelle microemulsions. This method provides selective deposition of metal nanoparticles on Si surfaces versus oxidized Si surfaces. We use GD deposition of Au nanoparticles for Si nanowire growth along <111> and <110> directions, as well as for horizontal nanowire growth in prefabricated microtrenches on a Si substrate. Previous results indicate that a narrow distribution of Si nanowire diameters seems to be difficult to achieve by GD deposition of gold catalyst nanoparticles. Here we compare the distribution of diameters of Si nanowires grown from gold catalyst nanoparticles deposited from colloidal suspensions and from reversed micelle microemulsions via GD. Our results show that the optimization of several parameters that govern the GD processes, such as the metal ion concentration and substrate immersion time, leads to results comparable to those obtained with commercially available gold colloids. We also explore the deposition of other metals relevant for Si nanowire growth such as Cu or Pt. Our work shows that galvanic displacement deposition of metal catalyst nanoparticles provides important advantages for the growth of semiconductor nanowires: selective deposition on non-oxidized semiconductor surfaces, good nanowire diameter distribution and possibility of using different metals. |