Diameter-controlled and surface-modified Sb₂Se₃ nanowires and their photodetector performance

Due to its direct and narrow band gap, high chemical stability, and high Seebeck coefficient (1800 μVK^-1), antimony selenide (Sb₂Se₃) has many potential applications, such as in photovoltaic devices, thermoelectric devices, and solar cells. However, research on the Sb₂Se₃ materials has been limited by its low electrical conductivity in bulk state. To overcome this challenge, we suggest two kinds of nano-structured materials, namely, the diameter-controlled Sb₂Se₃ nanowires and Ag₂Se-decorated Sb₂Se₃ nanowires. The photocurrent response of diameter-controlled Sb₂Se₃, which depends on electrical conductivity of the material, increases non-linearly with the diameter of the nanowire. The photosensitivity factor (K = I_light/I_dark) of the intrinsic Sb₂Se₃ nanowire with diameter of 80-100 nm is highly improved (K = 75). Additionally, the measurement was conducted using a single nanowire under low source-drain voltage. The dark- and photocurrent of the Ag₂Se-decorated Sb₂Se₃ nanowire further increased, as compared to that of the intrinsic Sb₂Se₃ nanowire, to approximately 50 and 7 times, respectively.