Growth of InAs/GaAs quantum dots on Si, Ge/Si and germanium-on-insulator-on-silicon (GeOI) substrates emitting in the 1.3 μm band for silicon photonics

We report the growth of self-assembled InAs/GaAs quantum dots (QDs) on Si, Ge/Si and germanium-on-insulator-on-silicon (GeOI) substrates by metal organic chemical vapor deposition. GaAs layers with lower surface roughness (root mean square roughness of 1 nm) and higher structural quality were obtained on Ge/Si and GeOI compared to those obtained on Si substrate. We showed that the introduction of a QD layer within the GaAs buffer layer was efficient in suppressing the propagation of anti-phase domains to the GaAs surface for both cases of Ge/Si and GeOI substrates. Coalescence-free QDs with densities above 1010 cm−2 and ground state emission in the 1.3 μm band at room temperature were obtained on all substrates. QDs grown on GeOI yield the highest photoluminescence (PL) intensity, and quite remarkably, have similar PL intensity as those grown on GaAs substrate. These results suggest the better suitability of GeOI substrate compared to Si or Ge/Si substrates for the monolithic integration of QD-based lasers on silicon (or any other III–V photonic device) for silicon photonics.