In situ, atomic force microscope studies of the evolution of InAs three-dimensional islands on GaAs(001)

Abstract

The size evolution of molecular beam epitaxy-grown strained InAs three-dimensional (3D) islands on GaAs(001) is examined using in situ ultrahigh vacuum atomic force microscopy. Remarkably, just after the initiation of well-formed 3D islands at ∼1.57 ML InAs deposition, the lateral size dispersion and average value are found to first increase drastically with the smallest amount (∼0.05 ML) of additional InAs deposition and then decrease and saturate, indicating the onset of a natural tendency for size equalization, including through loss of material from the initially formed largest islands. These observations are found to be consistent with the previously suggested island-separation dependent influence of the evolving island-induced substrate strain fields on the adatom migration and incorporation/detachment kinetics that control the evolution of the islands.