GeSn Lasers for CMOS Integration



 In search of a suitable CMOS compatible light source many routes and materials are under investigation. Si-based group IV (Si)GeSn alloys offer a tunable bandgap from indirect to direct, making them ideal candidates for on-chip photonics and nano-electronics. An overview of recent achievements in material growth and device development will be given. Optically pumped waveguide and microdisk structures with different strain and various Sn concentrations provided direct evidence of gain in these alloys and of the width of the emission wavelength range that can be covered. With the final aim being the fabrication of electrically pumped lasers, a set of different homojunction light emitting diodes and more complex heterostructure SiGeSn/GeSn LEDs is presented. Detailed investigations of electroluminescence spectra indicate that GeSn/SiGeSn heterostructures will be advantageous for future laser fabrication.