Micron-Scale Photodetectors Based on One-Dimensional Single-Crystalline Sb2–xSnxSe3 Microrods: Simultaneously Improving Responsivity and Extending Spectral Response Region

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Among various one-dimensional (1D) materials, antimony selenide (Sb 2 Se 3 ) has the large visible to near-infrared (vis–NIR) absorption cross section and excellent stability; thus, it shows a huge potential to be applied as photodetectors. However, low electrical conductivity (10 –6 Ω –1 ·m –1 in bulk state) largely limits the extensive applications of Sb 2 Se 3 . By a hot-injection-based Sn/Sb substitution strategy, we prepare 1D Sb 2– x Sn x Se 3 microrods to further improve photodetecting performances of Sb 2 Se 3 microrods. Phase and microstructural analysis revealed the formation of orthorhombic 1D Sb 2– x Sn x Se 3 microrods with the length of 20–30 μm. From Hall effect measurements and absorption spectra, the Sb 2– x Sn x Se 3 microrods were evidenced as a p-type semiconductor with a higher electrical conductivity (6.95 × 10 –4 Ω –1 ·m –1 ) and a smaller band gap (0.97 eV) compared with Sb 2 Se 3 microrods. Accordingly, the photodetector based on a single Sb 2– x Sn x Se 3 microrod exhibited a remarkable response to 980 nm light at 10 V with a high responsivity (1.84 × 10 4 A·W –1 ), a fast response/recovery time (0.134 s/0.153 s), and a long-term durability. Because of the small band gap, the photodetector also exhibited a broadband photoresponse at vis–NIR spectral range. Given their high-responsivity and broadband response, the photodetector based on a single Sb 2– x Sn x Se 3 microrod is a promising candidate for applications in next-generation microdevices.