Heterostructures of MoS2 nanofilms on TiO2 nanorods used as field emitters

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

“…The ∼4 nm thick MoS 2 shell on β-TiO 2 nanorods gives the lowest values of E on (i.e., 2.5 V/μm for current density of 10 μA/cm 2 ) compared with anatase and rutile phases of various 1D TiO 2 nanostructures such as nanotip, nanotubes, nanorods, nanowires, nanoneedles, nanoflowers, and 3D microspheres. ,,, In addition, the formation of nanometric layers of MoS 2 over β-TiO 2 nanorods provided lower E on compared with pure MoS 2 thin films in the form of protrusions (i.e., 2.8 V/μm) and sheets (3.5 V/μm) on Si substrate. Furthermore, our results show much lower values of E on than those reported for carbon-doped (i.e., 21.9–5.0 V/μm), Fe-doped (i.e., 12 V/μm), and N-doped (i.e., 10, 9.21, and 6.54 V/μm) anatase TiO 2 nanotubes and the composites of MoS 2 @TiO 2 , and MoS 2 @SnO 2 . Moreover, these MoS 2 /β-TiO 2 /Si emitters appear to be better than the MoS 2 @TiO 2 heterostructure array delivering E on of 11 V/μm at a current density of 10 μA/cm 2 and hierarchical MoS 2 @SnO 2 hetero-nanoflowers delivering E on of 3.4 V/μm at a very low current density of 1 μA/cm 2 .…”

“…Furthermore, our results show much lower values of E on than those reported for carbon-doped (i.e., 21.9–5.0 V/μm), Fe-doped (i.e., 12 V/μm), and N-doped (i.e., 10, 9.21, and 6.54 V/μm) anatase TiO 2 nanotubes and the composites of MoS 2 @TiO 2 , and MoS 2 @SnO 2 . Moreover, these MoS 2 /β-TiO 2 /Si emitters appear to be better than the MoS 2 @TiO 2 heterostructure array delivering E on of 11 V/μm at a current density of 10 μA/cm 2 and hierarchical MoS 2 @SnO 2 hetero-nanoflowers delivering E on of 3.4 V/μm at a very low current density of 1 μA/cm 2 . However, turn-on fields of 2.2 and 2.5 V/μm were observed for the composite of MoS 2 layers heavily loaded over rutile TiO 2 hierarchical spheres of diameter >2.5 μm and rutile TiO 2 nanoparticles heavily enclosed over p-type MoS 2 flowerlike spheres of diameter 2 μm .…”

“…The β FE values of 1687, 680, and 1209 and 2465, 1398, and 6331 are estimated for low-field region and high-field region, respectively, observed in MoS 2 /β-TiO 2 /Si emitters coated with ∼40, ∼20, and ∼4 nm thick layers of MoS 2 , respectively. The values of β FE for MoS 2 /β-TiO 2 /Si emitters are higher than the values obtained for anatase and rutile phase of pure TiO 2 nanorods and nanotubes, , nanoparticle-decorated TiO 2 nanotubes, Fe- and N-doped TiO 2 nanotubes, , MoS 2 @TiO 2 heterostructures, MoS 2 @SnO 2 hetero-nanoflowers, nano-heterojunctions of ZnO nanoparticles, and MoS 2 layers over rutile TiO 2 nanorods. , Nevertheless, the orthodoxy test utilizing spreadsheet provided by Forbes in ref was performed to verify the feasibility of the FE measurements of MoS 2 /β-TiO 2 /Si emitters, especially, field enhancement factor (β FE ). The scaled-barrier-field ( f ) values evaluated for MoS 2 /β-TiO 2 /Si emitters coated with ∼40, ∼20, and ∼4 nm thick layers of MoS 2 are given in Table .…”

“…Moreover, morphology characterized by randomly oriented 1D nanostructures of high areal density suffers from significant field screening effect, thereby exhibiting poorer FE behavior. Furthermore, randomly distributed anatase TiO 2 nanorods covered with dense MoS 2 thin film provided the turn-on field of 11 V/μm, 24 which is very high compared to pure TiO 2 nanostructures and MoS 2 layers reported in the literature. Consequently, for promising FE behavior, it is of scientific and technological importance to grow vertically aligned 1D β-TiO 2 nanorods and furthermore tailor their electronic properties via the formation of heterostructure with an ultrathin 2D MoS 2 layer.…”

Hierarchical hexagonal boron nitride nanowall–diamond nanorod heterostructures with enhanced optoelectronic performance

“…1012 Direct fabrication of the 1D heterostructures with controlled structural characteristics (comprising morphology, surface architectures, dimensionality, and crystal structures) signifies an important challenge in the field of nanoscience and nanotechnology. Recently, heterostructures, such as ZnO-Zn3P2, 2 ZnS-In, 13 In2O3-Ga2O3, 14 CdS-CdSe, 15 ZnO-ultrananocrystalline diamond, 16 ZnSe/GeSe, 17 InAs-InP, 18 Ag-Ag2S, 19 MoS2-TiO2, 20 and hBN-carbon nanotubes, 21 have exhibited great potential in the field of photodetectors, energy storage devices, solar cells and field electron emitters.…”