The dependence of the growth-mode transitions in the InAs/GaAs nanostructures on the As/In ratio and the substrate temperature was investigated by using the intensity variation of the reflection high-energy electron-diffraction (RHEED) patterns, and the dependence Of the surface morphologies of the InAs layers on the substrate temperature was studied by using atomic force microscopy (AFM) images. The RHEED intensities Lire dramatically affected by changing the As/In ratio and the growth temperature, and the AFM images are significantly affected by varying the growth temperature. These results can help improve understanding of the formation processes for the InAs wetting layer and for the quantum dots, Lis well Lis the stain effect. (C) 2004 Elsevier B.V. All rights reserved.