TEM analysis of the size distribution of large self-assembled InAs/GaAs island structures

摘要

The size distribution of large, self-assembled InAs islands grown by metalorganic vapour phase epitaxy on (001) GaAs has been investigated by transmission electron microscopy. The layers grown at 500°C resulted in large dome-shaped islands, ranging from 29 to 183 nm in length. These islands were characterised by a uniform size distribution, with the islands clearly differentiable into specific size groups. The size distribution was found to be controlled by the addition of misfit dislocations (MD) as the islands grew from one size group to the next. Substantially increasing the growth time resulted in a bimodal size distribution of pyramidal islands. The large micron sized islands could also be categorised into particular size groupings, numbering nearly the same as that found for the nano-sized islands.