Individual Bi₂S₃ Nanowire-Based Room-Temperature H₂ Sensor

Single Bi 2 S 3 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 H 2 sensing performance that can detect H 2 (in N 2 ) 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) H 2 sensors. The sensing mechanism of Bi 2 S 3 nanowire devices is found to be different from that of other sensors based on nanowires or nanotubes. Experiments on different H 2 concentrations and gas pressures suggest that the sensing response is determined mainly by the amount of H 2 molecules instead of the proportion of H 2 in the mixed gas.