WS2 Nano-petals and Nano-bristles Supported on Carbon Nanotubes for Electron Emission Applications

Abstract

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.

In2Se3 Nanocubes as High Current Density Cold Cathode Materials

“…In addition, enhanced FE performance from WS 2 nanotubes emitter was reported by Viskadouros et al The authors have observed remarkable emission current stability over more than 18 h of continuous operation. Recently, studies on WS 2 nano-petals and nano-bristles supported on carbon nanotubes for FE applications have been reported . Di Bartolomeo et al have reported a gate-controlled field emission current from a WSe 2 monolayer, synthesized by chemical vapor deposition on a SiO 2 /Si substrate .…”

“…Recently, studies on WS 2 nano-petals and nanobristles supported on carbon nanotubes for FE applications have been reported. 36 39 Very recently, synthesis of a finger-like MoS 2 @VS 2 micro−nanocomposite with enhanced FE performance has been reported. 40 The group working from Pune University has carried out studies on FE performance of variety of 2D TMD nanostructures and nanocomposites.…”

Low-Temperature Physical Adsorption for the Nucleation of Sub-10 nm Al2O3 Gate Stack on Top-Gated WS2 Transistors

“…XPS was used to characterize the chemical reaction between the NL and WS 2 since the chemical shift is correlated with the surface states, ,, The W 4f and S 2p XPS spectra of the as-exfoliated WS 2 and the WS 2 deposited with the Al 2 O 3 NL are shown in Figure a,b, respectively, where the NL was prepared at 50 °C with a short purge time of 1 s. As compared with the binding energy of W 4f (∼35.4 and 33.2 eV) and S 2p (∼164.1 and 162.9 eV) peaks of the as-exfoliated WS 2 , no chemical shift appears in WS 2 covered with the Al 2 O 3 NL. Note that the W 4f doublet located at ∼36 and ∼38 eV because tungsten oxidation is not observed, indicating that the Al 2 O 3 NL deposition based on low- T physical adsorption did not give rise to the oxidation of tungsten. , The XPS measurement confirms that the NL deposition is predominated by the physical adsorption without surface chemical reactions.…”

“…Note that the W 4f doublet located at ∼36 and ∼38 eV because tungsten oxidation is not observed, indicating that the Al 2 O 3 NL deposition based on low-T physical adsorption did not give rise to the oxidation of tungsten. 6,23 The XPS measurement confirms that the NL deposition is predominated by the physical adsorption without surface chemical reactions.…”