INDIUM DISTRIBUTION IN INGAAS QUANTUM WIRES OBSERVED WITH THE SCANNING TUNNELING MICROSCOPE

The incorporation of In in the growth of crescent-shaped In0.12Ga0.88A s quantum wires embedded in (AlAs)(4)(GaAs)(8) superlattice barriers i s studied in atomic detail using cross-sectional scanning tunneling mi croscopy. It is found that the In distribution in both the surface and the first subsurface layer can be atomically resolved in the empty- a nd filled-state images, respectively. Strong In segregation is seen at the InGaAs/GaAs interfaces, but neither an expected enhancement of th e In concentration at the center of the quantum wire compared to the p lanar quantum well nor In clustering beyond the statistical expectatio n is observed. (C) 1995 American Institute of Physics.