Chemical Vapor Deposition Growth of Atomically Thin SnSb₂Te₄ Single Crystals Toward Fast Photodetection

SnSb2Te4 (SST), a ternary van der Waals (vdW) material, has been widely investigated during last decades for potential applications in superconductivity, thermoelectricity, and optoelectronics. Recently, atomically thin SST has been predicted to show abnormal electronic band structure evolutions, high carrier mobility, and strong light-matter interaction. However, controllable synthesis of such SST crystals has been a huge challenge. Herein, atomically thin SST flakes are prepared via a chemical vapor deposition (CVD) method by using SbCl3, SnCl45H(2)O, and Te as the precursors. Multiple structural characterizations reveal that the SST flakes are single crystals with high crystallinity. Due to the narrow bandgap of 0.42 eV, SST-based photodetectors have a broadband spectrum detection range from visible light through communication bands (480-1550 nm). More importantly, benefiting from a high room-temperature carrier mobility over 300 cm(2) V-1 s(-1), the SST photodetectors demonstrate a response/recovery time of tens of tens of microseconds, which exceeds most typical transition metal dichalcogenide (TMDC) flakes. In addition, the photodetector maintains high performance after being exposed to the air for 2 months, suggesting good environmental stability. These excellent performances suggest that the SST flakes are promising for next-generation optoelectronics.