Preparation of vertically aligned two-dimensional SnS2 nanosheet film with strong saturable absorption to femtosecond laser

Abstract

Vertically standing SnS2 film on transparent quartz was prepared by sulfuration of Sn film deposited by magnetron sputtering method. X-ray diffraction pattern and Raman spectrum of the film indicate its good crystallinity with a layered structure. Scanning electron microscope images of the film clearly demonstrate its vertically standing structure. The thickness of a single SnS2 nanosheet is measured to be 18.4 nm according to the cross-section height profile of the atomic force microscope image. The nonlinear optical response of SnS2 nanosheet film is investigated by using the open aperture Z-scan technology with a femtosecond pulsed laser (400 fs) working at 1064 nm. The modulation depth (αs) and saturable absorption intensity (Isat) of SnS2 film are measured to be 11.7% and 1.9 MW cm−2, respectively. The Z-scan results reveal that the SnS2 nanosheet film exhibits strong saturable absorption behavior to the femtosecond laser, making it have potential applications in mode-locked lasers for femtosecond pulses generation.