Enhanced Broadband Responsivity of Ni-Doped Sb2Se3 Nanorod Photodetector

Antimony selenide (Sb2Se3) semiconductor with a narrow band gap is regarded as an ideal candidate for the next-generation broadband photodetectors. However, the photodetectors based on the binary Sb2Se3 semiconductor suffer from low responsivity (Rλ) and external quantum efficiency due to the intrinsic low electrical conductivity. To address the issue, we introduce a low-valence Ni cation (Ni2+) into the binary Sb2Se3 ((Sb1–xNix)2Se3) nanorods synthesized by a facile hot-injection process. With increasing Ni-doping concentration, the (Sb1–xNix)2Se3 nanorods exhibit a significant increase of electrical conductivity from 4.983 × 10–5 to 4.011 × 10–4 Ω–1 m–1. The photodetector based on (Sb0.995Ni0.005)2Se3 nanorod film exhibits an excellent responsivity of 18.9 mA/W under white light illumination of 45 mW/cm2 at an applied bias voltage of 3 V, which is an approximately 19-fold higher than that of the pristine Sb2Se3 nanorod photodetector. Moreover, the density functional theory calculation has demonstrated t...