ONLINE Halbleiter zum Frühstück - Light from Silicon

Silicon and germanium cannot emit light efficiently due to their indirect bandgap, hampering the development of Si-based photonics. However, alloys of SiGe in the hexagonal phase are predicted to have a direct band gap. In this work, we demonstrate the realization of this new material and the direct band gap properties. We show efficient light emission up to room temperature accompanied by a short radiative life time, the hallmarks of a direct band gap material. The band gap energy is tunable in the range of 0.35 till 0.7eV opening a plethora of new applications. We finally discuss possible routes to integrate this material in Si- technology.