Assembling strained InAs islands by chemical beam epitaxy

We report on coherently strained InAs quantum-dots grown by chemical beam epitaxy on GaAs. The morphological phase transition of the InAs layer from two-dimensional to three-dimensional was characterized with reflection high-energy electron diffraction. The transition is found to be quasi-equilibrium in the slow deposition regime studied, to be approximately linear in InAs thickness, and to be suppressed both by higher temperature and As pressure. Patterned substrates were used to assemble the dots in specific locations. Conditions were found to align dots in chains of several-mu m length, to place small numbers of dots in holes, and to grow riots only within patterns but not on adjoining flat surfaces. When capped with GaAs, the islands are optically active.