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

We report comparative field electron emission (FE) studies on a large-area array of two-dimensional MoS₂-coated @ one-dimensional (1D) brookite (β) TiO₂ 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-TiO₂ nanorods were coated with MoS₂ 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/cm² observed for MoS₂-coated 1D β-TiO₂ nanorods emitters is significantly lower than that of doped/undoped 1D TiO₂ nanostructures, pristine MoS₂ sheets, MoS₂@SnO₂, and TiO₂@MoS₂ heterostructure-based field emitters. The orthodoxy test confirms the viability of the field emission measurements, specifically field enhancement factor (β_FE) of the MoS₂@TiO₂/Si emitters. The enhanced FE behavior of the MoS₂@TiO₂/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 TiO₂ nanorods. Furthermore, these MoS₂@TiO₂/Si emitters exhibit better emission stability. The results obtained herein suggest that the heteroarchitecture of MoS₂@β-TiO₂ 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.