Surface reconstruction and morphology evolution in highly strained InAs epilayer growth on GaAs(001) surface

Novel planar growth of highly strained heterostructure of InAs/GaAs(0 0 1) by molecular beam epitaxy (MBE) has been studied by an in situ scanning tunneling microscope (STM) and reflection high-energy electron diffraction (RHEED). It is found that deposition of submonolayer indium on the GaAs As-rich 2 x 4 substrate produces a new 4 x 2 reconstruction, and a novel layer-by-layer growth of multilayers of InAs can be achieved when the growing front displays this 4 x 2 symmetry. Here, we will discuss the atomic structure of the 4 x 2 reconstruction, based on the voltage-dependent high-resolution STM images. In addition. a new strain relaxation mechanism - domain wall structure, in terms of the present novel planar growth mode, will also be addressed.