Nano-Heteroarchitectures of Two-Dimensional MoS₂@ One-Dimensional Brookite TiO₂ Nanorods: Prominent Electron Emitters for Displays

Abstract

We report comparative field electron emission (FE) studies on a large-area array of two-dimensional MoS 2 -coated @ one-dimensional (1D) brookite (β) TiO 2 nanorods synthesized on Si substrate utilizing hot-filament metal vapor deposition technique and pulsed laser deposition method, independently. The 10 nm wide and 760 nm long 1D β-TiO 2 nanorods were coated with MoS 2 layers of thickness ∼4 (±2), 20 (±3), and 40 (±3) nm. The turn-on field ( E on ) of 2.5 V/μm required to a draw current density of 10 μA/cm 2 observed for MoS 2 -coated 1D β-TiO 2 nanorods emitters is significantly lower than that of doped/undoped 1D TiO 2 nanostructures, pristine MoS 2 sheets, MoS 2 @SnO 2 , and TiO 2 @MoS 2 heterostructure-based field emitters. The orthodoxy test confirms the viability of the field emission measurements, specifically field enhancement factor (β FE ) of the MoS 2 @TiO 2 /Si emitters. The enhanced FE behavior of the MoS 2 @TiO 2 /Si emitter can be attributed to the modulation of the electronic properties due to heterostructure and interface effects, in addition to the high aspect ratio of the vertically aligned TiO 2 nanorods. Furthermore, these MoS 2 @TiO 2 /Si emitters exhibit better emission stability. The results obtained herein suggest that the heteroarchitecture of MoS 2 @β-TiO 2 nanorods holds the potential for their applications in FE-based nanoelectronic devices such as displays and electron sources. Moreover, the strategy employed here to enhance the FE behavior via rational design of heteroarchitecture structure can be further extended to improve other functionalities of various nanomaterials.

Edge‐Enriched Ultrathin MoS2 Embedded Yolk‐Shell TiO2 with Boosted Charge Transfer for Superior Photocatalytic H2 Evolution

“…The binding energies of 163.5 and 162.3 eV are associated with the S 2p 1/2 and S 2p 3/2 of S 2− anion in MoS 2 . Remarkably, the energy separation in Mo (3p 3/2 and 3p 5/2 ) and S (2p 1/2 and 2p 3/2 ) orbit are 3.2 eV (<3.3 eV) and 1.2 eV (<1.4 eV), respectively, due to the formation of MoS 2 . For the UMT‐0.14 hybrid, however, the binding energies of the Mo 4+ species in the composite obviously are shifted to lower binding energies by 1.0 (Mo 3p 3/2 ) and 0.9 eV (Mo 3p 5/2 ), which are caused by the injected electrons transfer to the d orbital of the Mo centre in the transition metal dichalcogenide.…”

The effect of stoichiometry on the structural, thermal and electronic properties of thermally decomposed nickel oxide

“…However higher binding energy peak observed at 531.1 represents the surface contamination or presence of hydroxyl (-OH) groups. [38][39][40][41] The close analysis of decomposed XPS spectrum revealed that the intensity of the peaks assigned to core levels of Ni 3+ (2p 3/2 ) and Ni 3+ (2p 1/2 ) is larger than that of core levels Ni 2+ (2p 3/ 2 ) and Ni 2+ (2p 1/2 ) at decomposition temperature of 400 and 500 C. However, the intensity of the peaks of Ni 2+ (2p 3/2 ) and Ni 2+ (2p 1/2 ) core levels has increased than that of peaks of Ni 3+ (2p 3/2 ) and Ni 3+ (2p 1/2 ) core levels aer the decomposition temperature of 700 C and are continued to increase for the temperature of 1100 C. The intensity ratio obtained for the peaks of the Ni 2+ (2p 3/2 ) and Ni 3+ (2p 3/2 ) core levels (i.e. Ni 2+ / Ni 3+ ) has increased from 0.85 (AE0.03) to 1.23 (AE0.03) with an increase in the temperature from 400 to 1100 C. Moreover, the variation in the intensity of the core levels assigned to the Ni 2+ and Ni 3+ is more apparent at decomposition temperature of 500 and 700 C in Fig.…”

Toward the use of CVD-grown MoS2 nanosheets as field-emission source

“…Due to their exposed sharp edges, un-stacked morphology and high aspect ratio they are less affected by Joule heating [ 11 ]. In the past few years, FE measurements on different MoS 2 morphologies, such as horizontally arranged (with a few protruding portions) MoS 2 [ 12 ], sparsely distributed vertically aligned MoS 2 NSs [ 9 ], MoS 2 nanoflowers [ 13 ] and MoS 2 nano-heteroarchitectures [ 14 ] have been reported. The semiconducting MoS 2 NSs with exposed edges could significantly enhance the FE properties [ 9 ].…”