Structural and optoelectronic properties of germanium-rich islands grown on silicon using molecular beam epitaxy

We report on the structural and optoelectronic properties of self-assembled germanium-rich islands grown on silicon using molecular beam epitaxy. Raman, photocurrent, photoluminescence, and transient optical spectroscopy measurements suggest significant built-in strains and a well-defined interface with little intermixing between the islands and the silicon. The shape of these islands depends on the growth conditions and includes pyramid, dome, barn-shaped, and superdome islands. Most importantly, we demonstrate that these germanium-rich islands provide efficient light emission at telecommunication wavelengths on a complementary metal-oxide semiconductor-compatible platform.