As an emerging semiconductor nanomaterial, antimony selenide (Sb 2 Se 3 ) not only shows great potential in optoelectronic detection and thermoelectric devices due to its excellent properties such as strong anisotropy, wide-spectrum photoresponse, stable phase structure, and large Seebeck coefficient but its characteristics of narrow bandgap, high absorption coefficient, and good carrier mobility also make it advantageous for application in ultrafast optics. However, to date, there have been no reports of Sb 2 Se 3 in a mode-locked Er-doped fiber laser (EDFL). In this work, we successfully and controllably grew Sb 2 Se 3 nanosheets and nanowires via chemical vapor deposition and for the first time employed them as saturable absorbers to achieve mode-locked laser output. The grown nanosheets exhibited high crystallinity and sizes up to 45 μm. The mode-locked EDFL based on nanosheet-tapered fiber achieved a pulse width as narrow as 609.12 fs, with stable spectra and a maximum output power of 5.81 mW in the mode-locked state. In contrast, the nanowire-tapered fiber achieved a pulse width of 743.17 fs, with a maximum output power of 4.988 mW. These findings demonstrate the promising application potential of Sb 2 Se 3 in ultrafast optics, providing further insights into the application of one-dimensional and twodimensional (2D) nanomaterials in this field. Additionally, this work also provides strong support for the development of 2D nanosheets growth from nonintrinsic 2D crystal structure materials.
