Seminar of Physics of Wrocław University of Technology
PWr, bud. A1, sala 322
An introduction to III-V nanowires on Silicon: the small structures with big potential
dr Faebian Bastiman
Paul-Drude-Institut für Festkörperelektronik/The University of Sheffield
Nanowires were first synthesized during the semiconductor boom of the 1960s. These intriguing structures are typically <30nm in diameter and range from a few 100 nms to tens of microns in length. Recently these structures have received significant interest from the areas of pure material science through to novel device architectures. Nanowires provide access to an exciting avenue that is often heralded as “the holy grail” of epitaxy: III-V integration on silicon substrates. Nanowires can be synthesized in a variety of ways with numerous growth techniques on a variety of substrates including silicon, metal and glass.
Catalysed nanowire growth was the original method and is still very popular. A metallic droplet acts as a catalyst for atoms which then condense to form crystalline layers. The early work used gold (Au) catalysts and whilst these can be used to form a range of elemental and compound nanowires even trace amounts of Au are incompatible with modern Si technology. More recently so called self-catalysed nanowires have become popular where the group III element of the III-V nanowire is used as the catalyst.
Nanowires even offer two further possibilities beyond the ability to integral III-V materials on Si. Firstly, the small nanowire dimensions also mean they can more readily deform and absorb strain without generating dislocations. This means new alloy combinations can be realised for the first time. Secondly, the cylindrical nanowire geometry enables the creation of new quantum radial and axial heterostructures that are not possible in conventional planar semiconductor architecture.
This talk introduces the field of III-V nanowire integration on Si substrates, including the history, recent progress, current problems and future outlook.
