Gas Sensing Mechanism of Gold Nanoparticles Decorated Single- Walled Carbon Nanotubes

Metal nanoparticles decorated single-walled carbon nanotubes (SWNTs) can lead to considerable enhancement in sensing performance towards different gas analytes, however the sensing mechanism was not clearly elucidated. The detailed sensing mechanism of hybrid gold-SWNT nanostructures toward hydrogen sulfide was investigated using field effect transistor (FET) transfer characteristics. At low H2S concentrations ( 100 ppbV), FET transfer characteristics show that the gold nanoparticles at the surface of SWNTs acted as nano-Schottky barriers to predominately modulate transconductance upon exposure to unfunctionalized SWNTs on gold electrodes which showed little or no response upon exposure. Although the sensitivity of Au/SWNT toward H2S was strongly dependent upon the size and number of gold nanoparticles, the sensing mechanism was independent of it.