Extended performance GeSn/Si(100) p-i-n photodetectors for full spectral range telecommunication applications

First-generation n-i-GeSn/p-Si(100) photodiode detectors with Ge _0.98Sn_0.02 active layers were fabricated under complementary metal oxide semiconductor compatible conditions. It is found that, even at this low Sn concentration, the detector quantum efficiencies are higher than those in comparable pure-Ge device designs processed at low temperature. Most significantly, the spectral range of the GeSn device responsivity is dramatically increased-to at least 1750 nm-well beyond the direct band gap of Ge (1550 nm). This allows coverage of all telecommunication bands using entirely group IV materials.