Isothermal Gas Flow Separation of Helical ZnS Nanowires and Straight Nanobelts

The growth of one dimensional wurtzite ZnS nanostructures with different crystallinity, shape, surface roughness, and crystal structure have been successfully separated at the same temperature zone by varying local gas flow in the vicinity of deposition substrates during a vapor phase deposition process. Through controlling local gas flow forms as either laminar flow or blocking flow, self-assembled ZnS nanostructures have been tailored into either single crystalline ZnS nanobelt with smooth surface, or polycrystalline/partially-crystalline helical nanowires with rough surface at similar to 600 degrees C. The deposited nanostructure morphology is sensitive to the change of local gas flow conditions as well. The different mass and composition gradient tuned through the incoming ZnS/Ar/CO (CO(2)) mixture gas flow are responsible for the isothermal nanostructures separation demonstrated here. The gas flow control over nanostructure morphologies might bring up new insights on nanoscale crystal growth and, add a new dimension in nanomaterials growth and control. Furthermore, this new growth strategy could shed light for scale-up manufacturing high yield complex semiconductor nanostructures like helical nanostructures in a rational and controlled way.