May 7, 2009
Gallium assists quest for superior nanowires
Semiconductor nanowires are expected to play an important role in XXI century advanced devices. For this to become a reality, gold has to be substituted with another metal that does not harm the electronic properties.
Scientists at the Walter Schottky Institute of the Technical University of Munich, Germany, and Ecole Polytechnique in France have found the way of synthesizing silicon nanowires by using gallium as a catalyst. Avoiding gold as a catalyst in the VLS process is believed to result in nanowires with superior electronic and optoelectronic properties.
The difficulty of using other metals than gold has always resided in the fast oxidation of metals, when oxygen is present even in small concentrations. Now researchers have come up with a novel way to avoid this. The synthesis of the nanowires is realized in a reducing environment, by producing a hydrogen radical rich plasma. The growth of nanowires with the use of plasma enhanced chemical vapor deposition (PECVD) has an additional advantage. The decomposition of the silicon precursor (SiH4) is started in the gas phase, facilitating the complete catalytic decomposition at the gallium surface.
The team presented its work in Nanotechnology.
About the author
Ilaria Zardo studied physics at the Sapienza in Rome and is currently realizing her doctoral studies under the supervision of Anna Fontcuberta i Morral and Gerhard Abstreiter at the Walter Schottky Institut of the Technical University of Munich. She is a Marie Curie Excellence Grant team member. Linwei Yu is a postdoctoral scholar in the group of Pere Roca I Cabarrocas at the Ecole Polytechnique (Palaiseau, France).