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

Among various one-dimensional (1D) materials, antimony selenide (Sb2Se3) 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 Sb2Se3. By a hot-injection-based Sn/Sb substitution strategy, we prepare 1D Sb2–xSnxSe3 microrods to further improve photodetecting performances of Sb2Se3 microrods. Phase and microstructural analysis revealed the formation of orthorhombic 1D Sb2–xSnxSe3 microrods with the length of 20–30 μm. From Hall effect measurements and absorption spectra, the Sb2–xSnxSe3 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 Sb2Se3 microrods. Accordingly, the photodetector based on a single Sb2–xSnxSe3 microrod exhibited a remarkable response to 980 nm light at 10 V with a high responsivity (1.84 × 104 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 Sb2–xSnxSe3 microrod is a promising candidate for applications in next-generation microdevices.