Search

The influence of Ga preadsorption on Si111, Si113 and Si112 surfaces on Ge growth has been investigated by lowenergy electron diffraction and microscopy as well as Xray photoemission spectroscopy. On Si111, step edges and substrate domain boundaries are decorated with Ga at high deposition temperatures, enabling selective growth and alignment of threedimensional Ge islands on a chemically modulated surface. On Si113, a morphological modulation is achieved by Ga saturation, as the Si substrate decomposes into an ordered array of 112 and 115 facets. This results in the growth of Ge islands aligned at the facets. These islands exhibit an anisotropy, as they are elongated along $1\bar 10$. Ga preadsorption on Si112 smoothens the initially faceted bare surface, and subsequent Ge growth leads to the formation of nanoscale Ge wires. The results are discussed in terms of surface chemistry, as well as diffusion and strain relaxation anisotropy.