Ge and GeSn Light Emitters on Si

The heteroepitaxial growth of GeSn and Ge crystals on Si substrates are investigated for Si-based photonic applications. Light Emitting Diodes with emission wavelengths from 2,100 to 1,550 nm could be demonstrated with active intrinsic GeSn light emitting layers between Ge barriers. A clear shift of the direct band gap toward the infrared beyond 2 μm is measured. Emission intensity is increased compared to Ge Light Emitting Diodes. Room temperature lasing from electrically pumped n-type doped Ge edge emitting devices are demonstrated. The edge emitter is formed by cleaving Si-Ge waveguide heterodiodes, providing optical feedback through a Fabry-Perot resonator. The electroluminescence spectra of the devices showed optical bleaching and intensity gain for wavelengths between 1,660 nm and 1,700 nm.