Enhanced field-emission of silver nanoparticle–graphene oxide decorated ZnO nanowire arrays

Abstract

This work presents a new method to improve the field emission (FE) properties of semiconductors decorated with low-cost graphene oxide (GO) nanosheets and trace amounts of noble metal. The Ag/GO/ZnO composite emitter exhibited efficient FE properties with a low turn-on field of 1.4 V μm(-1) and a high field enhancement factor of 7018. The excellent FE properties of the Ag/GO/ZnO composite can be attributed to the tunneling effect of electrons through the heterojunction. The FE properties of the Ag/GO/ZnO composite are slightly better than those of the Ag/ZnO composite which forms an energy well that collects electrons on interfaces when an electric field is applied. This behavior is associated with heterostructures that offer more contact points and protrusions between ZnO nanowire arrays (NWAs) and Ag/GO, which leads to easier electron transfer. High-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterise the connection and evolution of the ZnO NWAs and Ag/GO composites.

A novel non-invasive strategy for low-level laser-induced cancer therapy by using new Ag/ZnO and Nd/ZnO functionalized reduced graphene oxide nanocomposites

“…In addition to the peaks associated with the D and G bands of graphene, the Raman spectrum of the ZnO/rGO, Ag-ZnO/rGO and Nd-ZnO/rGO NCs shows a sharp and narrow peak at 443 cm À1 corresponding to the E2 (high) mode of the Raman active mode, a characteristic peak for the wurtzite hexagonal phase of ZnO. All Raman signals relative to rGO and ZnO could clearly be observed in the Ag-ZnO/rGO and Nd-ZnO/rGO NCs [46,47] [48]. Major peaks observed were attributed to Fg mode and Ag þ Eg combination modes [48].…”

“…Figure 6(a,b) indicate the corresponding C 1 s XPS spectra. The XPS data illustrate that all the samples possess the non-oxygenated ring C (284.5 eV, SP 2 ), the C-O bond in 286.5 eV and the O¼C in 288.2 eV [46,47]. In Figure 6(b), the ZnO/rGO NC, one peak with binding energy of 283.3 eV can be ascribed to the C-Zn bond which can formed during calcination at 400 C for 4 h. It is well known that the existence of C-O and C¼O in the GO bonds show the high intensity.…”

“…Based on the previously published articles, elimination of the GO peak in the as-synthesized NCs could be due to the presence of two factors: (i) the first is the low intensity and low diffraction intensity of GO in comparison to the ZnO diffraction intensity. And, on the other hand, (ii) the disappearance may form from the full growth of ZnO crystals on rGO plates that prevents the appearance of graphene oxide peak [46,47]. In Nd-ZnO/rGO and Ag-ZnO/rGO NCs, the observed XRD peaks were in complete accordance with hexagonal ZnO (h-ZnO) (card No.…”

Aqueous Phase Synthesis and Enhanced Field Emission Properties of ZnO-Sulfide Heterojunction Nanowires

“…In recent years, the high-performance cold cathode materials like carbon nanotubes and semiconductor nanowires or nanotubes, which possess a low turn-on voltage and a high emission current, are one dimensional (1D) nanostructures 16 17 18 19 . The results from 1D nanostructures, which show the high aspect ratio and small radius of curvature, exactly meet the requirements of good FE performance 18 19 20 21 22 . The 1D ZnO nanostructures have been extensively studied in the FE area, due to its inexpensive, nontoxic, and excellent physical and chemical properties 23 24 25 26 27 28 .…”

Well Oriented ZnO Nanorods Array: Negative Resistance and Optical Switching

“…Recently, one‐dimensional (1D) ZnO nanomaterials (NMs) have been vastly studied because both their functional properties and highly controllable morphology make them central building blocks for understanding nanoscale phenomena and realizing nanoscale devices , . Owing to its specific optical and electrical properties due to high surface to volume ratio and quantum confinement effect, one‐dimensional ZnO nanomaterials have great potential applications in nanogenerators, photocatalysis, surface acoustic waveguides,, humidity sensors,, as well as in light‐emitting diode, sensors, solar cells,, photodetectors,, optical switches, field emission devices,, and resistive random access random memory . In addition, surface functionalization or by coupling the different properties of ZnO based semiconducting hybrids can expand the ZnO NMs applications.…”