Individual GaAs quantum emitters grown on Ge substrates

We report on the nucleation of low density and defect-free GaAs quantum dots (QDs) on Ge substrates. The growth of III-V nanostructures was realized via droplet epitaxy technique. A detailed micro- and macro-photoluminescence analysis shows that the optical quality of the GaAs QDs is almost comparable with state-of-the-art QDs directly grown on GaAs substrates. Bright and sharp exciton and biexciton lines of individual QDs have been observed. This achievement opens the route to the realization of quantum optoelectronic devices on IV semiconductor substrates. (C) 2011 American Institute of Physics. [doi:10.1063/1.3560303]