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 (Sb 2 Se 3 ) has many potential applications, such as in photovoltaic devices, thermoelectric devices and solar cells. However, research on the Sb 2 Se 3 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 Sb 2 Se 3 nanowires and Ag 2 Se-decorated Sb 2 Se 3 nanowires. The photocurrent response of diameter-controlled Sb 2 Se 3 , 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 Sb 2 Se 3 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 Ag 2 Se-decorated Sb 2 Se 3 nanowire further increased, as compared to that of the intrinsic Sb 2 Se 3 nanowire, to approximately 50 and 7 times, respectively.