DFG Research Grant: SiGeSn-Nanostructures for Integrated Quantum Well Infrared Photodetectors

The project goal is the fabrication and characterisation of CMOS-compatible quantum-well infrared photodetectors based on n-type SiGeSn heterostructures operating in the mid-infrared and far-infrared wavelength ranges with possible applications in absorption-based gas sensing and imaging. Previous work on Group-IV based quantum well infrared photodetectors focused on utilizing SiGe multi-quantum well structures, however, the photoresponse cannot compete with commercial devices based on III-V heterostructure quantum wells. By exploiting the larger physical parameter tunability of the ternary alloy SiGeSn we intend to extend the potential of Group-IV-based detectors to demonstrate quantum-well infrared photodetectors with low manufacturing costs that can be interfaced directly with CMOS signal conditioning circuits for the development of ultra-compact integrated sensing solutions. To this end, we plan to experimentally investigate relevant material properties such as bandgap and band offsets of the ternary alloys, which, to date, are not sufficiently understood. Device realisation will then be based on theoretical modelling and experimental data from material growth to the device fabrication process.