Scanning tunneling microscopy observations of indium segregation phenomena on GaInAs layer grown by molecular beam epitaxy

The surface structures on a cation-stabilized GaInAs layer grown on an InP(001) substrate were observed using a scanning tunneling microscopy (STM) multi-chamber system equipped with a molecular beam epitaxy facility. The STM image of a cation-stabilized GaInAs surface showed the same structure as that of an In-stabilized InAs surface, which means that the In-stabilized InAs layer was formed on the grown GaInAs layer as a result of the indium segregation. We have also observed the indium segregation phenomena on a GaAs/InAs heterostructure. The STM image of an InAs substrate on which an amount of GaAs equal to half a monolayer was deposited revealed the formation of an InAs layer on the top of a two-dimensionally grown GaAs layer. This InAs layer was caused by the segregation of indium atoms from the InAs substrate through the deposited GaAs layer.