A study of the initial stages of the growth of Au-assisted epitaxial Ge nanowires on a clean Ge(100) surface

We report on the interfacial phenomena that occur at the initial stages of Ge nanowire growth using gold as the catalyst on Ge(100) substrates under ultra high vacuum (UHV) conditions using molecular beam epitaxy (MBE). Room temperature deposition of a thin Au layer using MBE showed a wetting nature while de-wetting has been observed at 500 °C and higher temperatures. The deposition of a thin layer of Ge at this condition resulted in the formation of Ge nanostructures and Au islands on Ge pedestals, corresponding to the initial growth of the Ge nanowires. Ge deposition at 600°C yielded larger Ge nanowires below the Au/AuGe catalyst interface due to the enhancement of the lateral material transport.