Self-organizing process of moderately strained Zn1-xCdxSe layer grown on GaAs(110) by molecular beam epitaxy

Self-organizing process of moderately strained Zn1-xCdxSe layer on the GaAs (110) surface was investigated during the molecular beam epitaxy (MBE). The GaAs(110) surface was prepared by cleavage in ultrahigh vacuum (UHV). In c ontrast to the ZnSe layers which have a mirror-like surface, two types of s urface structures were observed on the Zn1-xCdx Se layer, i.e. pyramidal-sh aped islands and asymmetric a-shaped ridges oriented parallel to the [110] direction, indicating that the strain relaxation process was not of a conve ntional Stranski-Krastanow type. The ridges were strong correlated with the underlying dislocations produced by anisotropic in-plane strain relaxation . Local variation in the growth rate due to periodic strain distributions c aused by the dislocations is suggested to be the formation mechanism of the ridge structures.