Ge Quantum Dots Encapsulated by AIAs Grown by Molecular Beam Epitaxy on GaAs without Extended Defects
MetadataShow full metadata
We demonstrate nearly spherical, strain-free, self-assembled Ge quantum dots (QDs) fully encapsulated by AlAs, grown on (100) GaAs by molecular beam epitaxy. The QDs were formed without a wetting layer using a high temperature, in situ anneal. Subsequent AlAs overgrowth was free from anti-phase domains and threading dislocations in cross section transmission electron microscopy. The straddling band alignment for Ge in AlAs promises strong and tunable confinement for both electrons and holes. The reflection high-energy electron diffraction pattern changed from 2 × 3 to 2 × 5 with anneal, which can be explained by surface reconstructions based on the electron-counting model.