American Institute of Physics, Applied Physics Letters, 7(104), p. 073113
DOI: 10.1063/1.4866278
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We demonstrate nearly-spherical, strain-free, self-assembled Ge quantum dots (QDs) fully encapsulated by AlAs, grown on (100) GaAs by molecular beam epitaxy (MBE). The QDs were formed without a wetting layer using a high temperature, in-situ anneal. Subsequent AlAs overgrowth was free from threading dislocations and anti-phase domains. The straddling band alignment for Ge in AlAs promises strong and tunable confinement for both electrons and holes. The reflection high-energy electron diffraction (RHEED) pattern changed from 2x3 to 2x5 with anneal, which can be explained by surface reconstructions based on the electron-counting model. ; Comment: 14 pages, 5 figures, submitted to Applied Physics Letters