Local structure of uncapped and Si-capped Ge/Si(100) self-assembled quantum dots

Local structure of uncapped and Si-capped Ge quantum dots on Si(100) has be en probed by extended x-ray absorption fine structure and x-ray absorption near-edge structure spectroscopy. It is found that the uncapped Ge dots are partially oxidized and partially alloyed with Si. The amount of Ge present in the Ge phase is found to be about 20-30%. In the Si-capped sample, Ge i s found to be dissolved in silicon, the fraction of Ge atoms existing as a Ge phase being less than 10%. (C) 2001 American Institute of Physics.