Towards nanomemories: Ge growth on naturally and artificially nanostructured Si surfaces

Quantum dots (QDs) grown on semiconductors surfaces are actually the main researchers' interest for applications in the forecoming nanotechnology era like nanotransistors and nanomemories. Novel approaches to form ordered patterns of homogeneous nanostructures consist of natural patterning induced by surface instabilities, as step bunching of Si(111) or misoriented Si(001) surfaces, and of nanolithographic techniques, as focused ion beam (FIB) or patterning by scanning tunneling microscopy (STM). Based on the analysis of STM images and movies we report on growth and arrangement of Ge islands on nanopatterned silicon. Several issues are discussed: substrate nanostructuring using different techniques, wetting layer growth, transition up to 3D islands formation and arrangement of QDs to form nanomemories.