Formation of uniform nanoscale Ge islands on Si(1 1 1)-7 × 7 substrate

We have reported the formation of uniform nanoscale Si islands (3.8 nm in diameter) on a Si(1 1 1)-7×7 substrate by using the stable reconstructed structure on the substrate as a template. It is very interesting to use the template as a method of quantum dot formation. We have tried to form the uniform nanoscale island of Ge on the Si(1 1 1)-7×7 substrate at various growth conditions (substrate temperature and annealing temperature) and observed the size distribution of Ge islands with a scanning tunneling microscope (STM). The range of substrate and annealing temperatures were chosen between 300 and 400°C. And we succeeded in the formation of uniform Ge islands showing a rounded shape with a diameter of 3.8 nm, when the Ge is deposited at 320°C and annealed at 360°C.