Momentum (k)-Space Charge Separation Mid-Wave Infrared Photodetectors Using SiGeSn Alloys

We report a band-structure engineering approach with k-space charge-separation feature by tailoring the direct-energy valley to be several k B T higher than the indirect, enabling large absorption coefficients while maintaining long-carrier lifetimes. Modeling shows SiGeSn alloys with constant 3k B TΓ - and L-valley separation cover MWIR range.