Excellent nonlinear absorption properties of 2D germanium nanosheets in the infrared band

Germanium, located in the group IVA, is a superior metalloid semiconductor material and has homologous properties to the congener element of silicene. However, the nonlinear properties of 2D germanium nanosheets in broadband (from ultraviolet to near-infrared) were rarely studied. From this perspective, in this work, we successfully prepared 2D germanium nanosheets by the liquid-phase exfoliation method and explored the nonlinear behavior of germanium nanosheets through the open aperture Z-scan technique. The experimental results proved that 2D germanium nanosheets exhibited excellent nonlinear optical potential in the infrared band. Our research is of great significance to inspire people to research germanium-like semiconductor materials and strengthen the nonlinear application of germanium.