Individual Bi2S3 nanowire-based room-temperature H2 sensor

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 H-2 sensing performance that can detect H2 (in N-2) at room temperature with a sensitivity of 22% at 10 ppm (corresponds to 4.0 x 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 Bi2S3 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.