Low-temperature synthesis of single crystalline Ag2S nanowires on silver substrates

We report on the successful synthesis of silver sulfide (Ag2S) nanowires by a simple and mild gas-solid reaction approach. For the nanowire synthesis, a preoxidized silver substrate is exposed to an atmosphere of an O-2/H2S mixture at room temperature or slightly above. The resulting Ag2S nanowires are phase pure with a monoclinic crystal structure and have diameters of a few tens of nanometers and lengths up to 100 mu m. The influence of reaction conditions on the diameter, length, and morphology of the Ag2S nanowires has been studied by a number of structural and spectroscopic techniques. The nanowire growth mechanism on the Ag substrate has been discussed, which is likely characterized by continuous deposition at the tip. Additionally, we demonstrate thinning and cutting of individual Ag2S nanowires with electron beams and laser beams, which are potentially useful for nanowire manipulation and engineering.