Chemical Identification on the Atomic Scale in MBE-Grown III-V Alloy Semiconductors

We have studied epitaxially grown III/V materials with cross-sectional scanning tunnelling microscopy, Using this method we can identify individual Al and Ga atoms in the ternary AlGaAs layers. Through this identification we observed clustering Al atoms in AlGaAs alloys. Furthermore cross-sectional scanning tunnelling microscopy can be used to study the growth history of quantum wells and quantum wires. As well, using this cross-sectional technique, one can observe individual electrically active dopant atoms. Through this sensitivity delta doped layers have been studied with atomic resolution where we observe Coulomb repulsion between active Be-doping atoms at high doping concentrations.