Patterned Growth of Nanoscale In Clusters on the Si(111)-7x7 and Si(111)-Ge(5x5) Reconstructions

Results of a study designed to investigate the possibility of using the Si(111)-Ge(5x5) surface reconstruction as a template for In cluster growth are described. As with Si(111)-7x7, the In adatoms preferentially adsorb in the faulted half-unit cell, but on Si(111)-Ge(5x5) a richer variety of cluster geometries are found. In addition to the clusters that occupy the faulted half-unit cell, clusters that span two and four half-unit cells are found. The latter have a triangular shape spanning one unfaulted and three, nearest neighbor, faulted half-unit cells, Triangular clusters in the opposite orientation were not found. Many of the faulted half-unit cells have a streaked appearance consistent with adatom mobility.