Horizontal GeSn/Ge multi-quantum-well ridge waveguide LEDs on silicon substrates

A horizontal p-i-n ridge waveguide emitter on a silicon (100) substrate with a Ge0.91Sn0.09/Ge multi-quantum-well (MQW) active layer was fabricated by molecular beam epitaxy. The device structure was designed to reduce light absorption of metal electrodes and improve injection efficiency. Flectroluminescence (EL) at a wavelength of 2160 nm was observed at room temperature. Theoretical calculations indicate that the emission peak corresponds well to the direct bandgap transition (n(1 Gamma )- n(1)(HH)). The light output power was about 2.0 mu W with an injection current density of 200 kA/cm(2). These results show that the horizontal GeSn/Ge MQW ridge waveguide emitters have great prospects for group-IV light sources. (C) 2020 Chinese Laser Press