SURFACE STUDIES ON MBE-GROWN III-V COMPOUNDS AND ALLOYS

The crystallographic and electronic surface properties of In//1// minus //xGa//xAs and GaSb//1// minus //yAs//y epitaxially grown on (100) oriented substrates have been investigated. The same surface reconstruction, a c(2 multiplied by 8), was observed for all values of x in In//1// minus //xGa//xAs. That of GaSb//1// minus //yAs//y was c(2 multiplied by 6) for y APP 1STH 0. 2 and, after a transition region, c(2 multiplied by 8) for y APP GRTH 0. 5. This transition region coincides with the change from acceptor to donor behavior of Sn in the alloy. The electronic surface properties of the two alloys differ as well. the differences in the crystallographic and electronic properties of the (100) surfaces of GaSb and GaAs derive from a different reconstruction mechanism, which may be attributed to differences in ionicities. The results suggest that the (100) surface of GaAs is a nonplanar surface.