In Situ Scanning Tunneling Microscope Observation of InAs Wetting Layer Formation on GaAs(001) during Molecular Beam Epitaxy Growth at 500 ℃

摘要

The evolution of InAs wetting layer growth on GaAs(001) was observed at 500 ℃ using scanning tunneling microscope within a molecular beam epitaxy growth chamber. In a series of island nucleation and step flow growth of InAs are clearly observed in the same region with each snapshot. The step density was increased with increasing of InAs growth due to island nucleation and recovered within one monolayer (ML) growth with coalescent-with two-dimensional islands. Actual step flow growth was stopped beyond 1 ML and then InAs quantum dots (QDs) were appeared at 1.72 ML. It is found that the excess amount of 3.9 x 10~(14) cm~(-2) In adatom independent from chemical bonding might be participate the formation of QDs induced with drastically around 1.7 ML.