Individual Bi₂S₃ Nanowire-Based Room-Temperature H₂ Sensor

Abstract

Single Bi2S3 nanowire devices were fabricated using the focused ion beam technique to deposit Pt electrodes. Repeatable and reliable ohmic contacts were obtained. The devices exhibit outstanding H2 sensing performance that can detect H2 (in N2) at room temperature with a sensitivity of 22% at 10 ppm (corresponds to 4.0 × 10−7 mol/L). Decorating Pd nanoparticles on the surface of the nanowire does not improve the sensing performance, contrary to most of the existing nanowire (or nanotube) H2 sensors. The sensing mechanism of Bi2S3 nanowire devices is found to be different from that of other sensors based on nanowires or nanotubes. Experiments on different H2 concentrations and gas pressures suggest that the sensing response is determined mainly by the amount of H2 molecules instead of the proportion of H2 in the mixed gas.