WS(2) Nano-petals and Nano-bristles Supported on Carbon Nanotubes for Electron Emission Applications

Atomically thin WS(2) nano-petals and nano-bristles were synthesized on vertically aligned carbon nanotubes (CNT) via magnetron sputtering at room temperature. The formation of the nano-petal morphology requires reaching a critical threshold in sputter deposition time, below which an amorphous film of WO(3) is obtained instead. Increasing the deposition time past a second threshold results in a change to the nano-bristle morphology. Both WS(2) nano-petals and nano-bristles were able to significantly enhance the electron emission of properties. The lowest turn-on voltage measured was to be 295 V and 355 V for the nano-petals and nano-bristles respectively, versus 425 V for pristine CNTs. The variation in the turn-on voltage is due to the electrical contacts at the interface between the different WS(2) structures, which induces current saturation at high emission currents. These results demonstrate that 2D WS(2) layers can be synthesized without the need for chemical routes and high growth temperatures if an appropriate template is employed.