Growth and Characterization of InAs Quantum Dots on GaAsSb

Abstract

The growth details of strained GaAsSb layers on GaAs(001) substrates were studied by reflection high energy electron diffraction (RHEED) beam intensity oscillations as a function of both substrate temperature and Sb/As flux ratio. Both the RHEED intensity and RHEED oscillation cycles are reduced with decreasing substrate temperature and Sb/As flux ratio. InAs QDs with high dot density, small dot size and narrow size distribution have been achieved on strained GaAs / GaAsSb buffer layer. The average lateral size of dots shows a trend toward to smaller size and dots’ density shows a trend toward to higher density as the surface Sb composition increasing. The QDs with higher density and smaller size distributions at high Sb composition, indicates that the Sb plays an important role in the dot formation under this growth condition. The lattice mismatch of InAs layer with the GaAsSb buffer layer is reduced with increasing of Sb composition in the GaAsSb interlayer. This result indicates that the density, size and size distribution of self-assembled quantum dots (QDs) can be controlled through the manipulation of the Sb-mediated strain field in the lattice mismatched system.