SURFACE AND SUBSURFACE IMAGING OF INDIUM IN INGAAS BY SCANNING-TUNNELING-MICROSCOPY

Investigating the ternary InxGa1-xAs alloy (x similar to 12%) by cross -sectional scanning tunneling microscopy, we find that on the UHV-clea ved (110) surface the In distribution in both the surface and the firs t subsurface layer can be atomically resolved in the empty- and filled -state images, respectively. This is found to be mostly a geometric ef fect due to the larger size of the In. We apply this method to study t he incorporation of In during the growth of In0.12Ga0.88As quantum wir es on nonplanar substrates, Strong In segregation in the growth direct ion is seen in the structure, and we compare the incorporation profile s across the quantum wire and a planar quantum well. No In clustering beyond the statistical expectation is observed.