Directed assembly of Ge islands grown on Au-patterned Si(100)

We have achieved two-db.mensional alignment of Ge islands grown by molecular beam epitaxy on Aupatterned Si(100). Arrays of Au dots are patterned by electron-beam evaporation of 1 nm of Au through a stencil mask. For a square array of Au dots, a two-dimensional square lattice consisting of Ge islands less than 100 mn in height extending over hundreds of micrometers has been realized. Surprisingly, the Ge islands are square-based, {111}-sideand (100)-top-faceted truncated pyrarrdds and grow at the centers of the squares formed by the Au-dot arrays. This novel growth process is a versatile method to manipulate island growth kinetics and thereby direct their assembly over large areas.