Growth and transformation of ultra-thin InAs/InP layers obtained by chemical beam epitaxy

We have studied the morphology of InAs layers grown on InP epitaxial surfaces and their evolution under cracked arsine anneal using atomic force microscopy. On an exactly oriented (001) surface, a 2 ML InAs layer annealed under arsine breaks into elongated dots oriented dong the [(1) over bar 10] direction. During annealing, the dot density first increases, then decreases, pointing to stages dominated by nucleation and by coalescence, respectively. Nucleation and filamentary growth of InAs is observed along the steps of a step-bunched InP surface, with an average misorientation of 0.8 degrees towards [110], while no localization can be achieved on surfaces tilted towards [(1) over bar 10]. A more homogeneous population of isotropic InAs dots with a base size dispersion as low as +/-10% is obtained when a silicon-doped InP buffer layer is used.