Turn-on Field Research Articles

The dopant (n- and p-type)-, band gap-, size- and stress-dependent field electron emission of silicon nanowires.

This study investigates the electron field emission (EFE) of vertical silicon nanowires (Si NWs) fabricated on n-type Si (100) and p-type Si (100) substrates using catalyst-induced etching (CIE). The impact of dopant types (n- and p-types), optical energy gap, crystallite size and stress on EFE parameters has been explored in detail. The surface morphology of grown SiNWs has been characterized by field emission scanning electron microscopy (FESEM), showing vertical, well aligned SiNWs. Optical absorption and Raman spectroscopy confirmed the presence of the quantum confinement (QC) effect. The EFE performance of the grown nanowire arrays has been examined through recorded J-E measurements under the Fowler-Nordheim framework. The Si NWs grown on p-type Si showed a minimum turn-on field and also a higher field enhancement factor. The band-bending diagram also suggests a lower barrier height of p-type Si NWs compared to n-type Si NWs, which plays a key role in enhancing the EFE performance. These investigations suggest that dopant types (n- and p-types), band gap, crystallite size and stress influence the EFE parameters and Si NWs grown on p-type Si (100) substrates are much more favorable for the investigation of EFE properties.

Influence of morphological characteristics of graphene on its field emission properties

Graphene is one of the most potential field emission cathode materials due to its excellent electrical, thermal, and mechanical properties, as well as rich edge structures. In this paper, we study the growth parameters of graphene prepared by chemical vapor deposition, and prepare three kinds of morphologies of graphene: single-layer graphene, graphene islands, and graphene with buffer layers, and then we explore the influence of the morphological characteristics of graphene on its field emission properties, and analyze the mechanism of influence of the morphological characteristics of graphene on its field emission properties through COMSOL. Comparing with single-layer graphene, the turn-on field of graphene islands and that of graphene with buffer layers decrease to 5.55 V/μm and 5.85 V/μm, respectively. The current densities also increase to 40.3 μA/cm<sup>2</sup> and 26.4 μA/cm<sup>2</sup>, respectively. On the other hand, the field emission currents of single-layer graphene and graphene with buffer layers are more stable. In a 5-hour test, the current densities only decrease by 2% and 4%, respectively. COMSOL simulation shows that the morphological characteristics of graphene have significant influences on the electric field distribution characteristics and heat dissipation capacity. Graphene islands and graphene with buffer layers have exposed edges, leading to local electric field concentration, and thus improving field emission properties. The graphene islands are distributed discretely on the substrate, forming no continuous graphene film and lacking transverse heat dissipation channels, so the accumulation of heat will cause damage to the graphene emitter, and affect the stability of its field emission current. This study will be of great benefit to the understanding of the influence of the morphological characteristics of graphene on its field emission properties, and improving the field emission properties of graphene materials.

Surface modification of a biomass-derived self-supported carbon nano network as an emerging platform for advanced field emitter devices and supercapacitor applications.

Herein, a self-supported carbon network is designed through the sole pyrolysis of Carica papaya seeds (biomass) without any activation agent, demonstrating their field emission and supercapacitor applications. The pyrolysis of seeds in an argon atmosphere leads to the formation of interconnected, rod-like structures. Furthermore, the hydrofluoric acid treatment not only removed impurities, but also resulted in the formation of CaF2 nanocrystals with the addition of F-doping. From the field emission studies, the turn-on field values defined at an emission current density of ∼10 μA cm-2 were found to be ∼2.16 and 1.21 V μm-1 for the as-prepared carbon and F-doped carbon, respectively. Notably, F-doped carbon exhibits a high emission current density of ∼9.49 mA cm-2 and has been drawn at an applied electric field of ∼2.29 V μm-1. Supercapacitor studies were carried out to demonstrate the multi-functionality of the prepared materials. The F-doped carbon electrode material exhibits the highest specific capacitance of 234 F g-1 at 0.5 A g-1. To demonstrate the actual supercapacitor application, the HFC//HFC symmetric coin cell supercapacitor device was assembled. The overall multifunctional applicability of the fabricated hybrid structures provides a futuristic approach to field emission and energy storage applications.

Size- and temperature-dependent optical, and electron field emission characteristics on SnO2 nanocrystals

Size-dependent SnO2 nanocrystals (NCs)) were synthesized using a co-precipitation technique. The particle size was varied by annealing the as-prepared SnO2 NCs with the estimated size of 2.3 nm at different temperatures. The particle size obtained was 4.7, 9.0, 15.4, 19.6, and 48.0 nm at annealing temperatures of 400, 600, 800, 1000, and 1200 °C, respectively. The XRD data revealed the tetragonal rutile structured for all SnO2 NCs. The temperature-dependent photoluminescence (PL) studies showed that the sub-bridging oxygen vacancy contributed dominantly compared to the in-plane and bridging oxygen vacancies at 5K. The function of nanocrystals’ size on field emission properties is also reported. The current density was high (1.9 μA/cm2) with modest the turn-on field (8.4 V/μm) for as-prepared SnO2 QDs with the lowest size (2.3 nm) compared to the high temperature annealed SnO2 nanocrystals.

Densification effect on field emission characteristics of CNT film emitters for electron emission devices

Field electron emission characteristics of the carbon nanotube (CNT) film emitters were investigated according to densification conditions such as nitric acid, acetic acid, and salicylic acid. The emission performance of the CNT film emitters was strongly affected by the densification conditions. Salicylic acid exhibits the best field electron emission properties of the CNT film emitters, followed by nitric acid and acetic acid. The efficient densification of the CNT film emitter by salicylic acid is caused by the role of polarity and p orbitals, nitric acid by hydrogen ions, and acetic acid by weak polarity. After the densification with salicylic acid, the turn-on field of the CNT film emitter decreases from 1.94 V μm−1 to 1.86 V μm−1, the threshold field decreases from 3.41 V μm−1 to 2.95 V μm−1, the emission current significantly increases from 20.92 mA to 43.98 mA, and the degradation rate from the long-term emission stability decreases from 49.9% to 21%. The improved emission characteristics are attributed to the increased emission sites at the CNT film and the increased electrical conductivity of the CNT film. The densification is a useful way to enhance the field electron emission properties of CNT film emitters.

Improved field emission properties of reduced graphene oxide decorated with indium nanoparticles

Low work function metals decoration of graphene is a effective method for the improvement of electron field emission properties. Indium, a relatively lower work function metal, is used to decorate reduced graphene oxide (RGO) films for the first time by simple and efficient solution process combined with magnetron sputtering method and the field emission properties are investigated. At continue voltage mode, the indium decorated RGO films display lower turn-on and threshold field as well as better emission stability than those of pristine RGO films. Moreover, the field emission performance of indium decorated RGO films is affected by the spacing between the cathode and anode. At pulse voltage mode, the indium decorated RGO films show approximately 10 times higher maximum emission current density compared to that at continue voltage mode. The calculation results by density functional theory indicate that the indium decoration of RGO significantly increases the density of states (DOS) near Fermi level and reduces the work function.

A two-dimensional hybrid of NiO nanowalls and reduced graphene oxide for superior field emission

The sharp and 2D nanostructure of nickel oxide (NiO) was synthesized hydrothermally on the nickel(Ni) foil and studied for field emission application. Graphene oxide (GO) and reduced graphene (rGO) is also good field emitter due to their unique electrical properties and geometry. The 2D_NiO nanostructured substrate was coated with GO solution, and it form a hetero-structure. The structure, morphology, and elemental details of as-synthesized materials, as well as hybrid samples, were determined by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS). The field emission study of the samples was studied for NiO nanostructures samples showed field emission response. The turn-on field and maximum currents are 7.5 V/μm and 4.9 mA/cm2; for graphene oxide coated Ni foil, Ni_GO sample, 14 V/μm, and the maximum current is 2.6 mA/cm2. With a coating of GO on the NiO nanostructured surface, the field emission response enhanced abruptly. In the hybrid sample, NiO_GO, the field emission response is enhanced abruptly, the turn-on the field and the maximum current are 5.7 V/μm and 15.5 mA/ cm2, respectively. The field emission response is substantially increased than that of the individual 2D nanostructure, which has shown a low field emission. The field emission response increased further, introducing rGO on the Nanostructured substrate. In the NiO_rGO sample, the turn-on field and the maximum currents are 4.4 V/μm and 39.6 mA/ cm2, respectively.

Nitrogen doped reduced graphene oxide: Investigations on electronic properties using X-ray and Ultra-violet photoelectron spectroscopy and field electron emission behaviour

The practice of heteroatom doping has been proven to significantly enhance the intrinsic properties of host materials. A facile, one-step process due to the thermal reduction of ammonium hydroxide-treated graphene oxide (GO) was employed to yield nitrogen (N) doped reduced graphene oxide (rGO). In-depth characterization has been performed to reveal the phase, structure, morphology, and electronic properties of as-synthesized products. It is observed that the processing temperature noticeably affects the concentration and type of doped N species. The N-doped rGO (N-rGO) prepared at 900 ℃ exhibited excellent field electron emission (FEE) performance with relatively lower values of turn-on and threshold fields ∼ 1.28 and 1.52 V/µm, defined at emission current densities of 10 and 100 µA/cm2, respectively. Furthermore, a high current density of 5.83 mA/cm2 was drawn at an applied field of 2.51 V/µm, and the emitter showed equitably current stability tested at 10 µA. The obtained results promote the N-rGO emitter, with tuned concentrations of doped N-species, as a promising candidate for practical applications in various vacuum microelectronic devices.

Field electron emission performance of Janus MoSSe and MoSSe-MWCNTs composite: Corroboration by Hall measurement and DFT simulation

Janus MoSSe and its composite with multiwalled carbon nanotubes (MWCNTs) have been synthesized using a facile one pot hydrothermal route. Formation of Janus MoSSe has been confirmed from the X-ray Diffraction, Raman, and X-ray Photoelectron spectroscopic analysis. Furthermore, field electron emission (FEE) behaviour of the as-synthesized Janus MoSSe and MoSSe-MWCNTs composite has been investigated at base pressure of ∼ 1 × 10−8 mbar in a planar diode configuration. Interestingly, the MoSSe-MWCNTs emitter exhibited enhanced FEE characteristics in terms of lower values of turn-on and threshold fields, competency to deliver large emission current density, in contrast to the pristine Janus MoSSe and MWCNTs emitters. An attempt has been made to reveal the underlying physics facilitating improvement in FEE behavior using computational analysis. In this regard, density functional theory (DFT) simulation was carried out to find electronic structure of the as-synthesized emitters. The DFT results indicate charge transfer from C 2p to Mo 4d orbitals, thereby enhancing electrical conductivity and reduction in work function of MoSSe-MWCNTs composite. Moreover, the experimental validation due to Hall measurements undoubtedly revealed noticeable increase in carrier concentration. The observed results clearly exemplify modulation electronic properties of Janus materials thereby highlighting their potential for various applications, including vacuum microelectronic devices.

Systematic synthesis of Bi2S3 nanoplates by template free solid-state approach and its field emission behaviour

We have demonstrated herewith controlled synthesis of Bi2S3 nanoplates by simple, template free, one step solid-state reaction at moderate temperature. The process parameters viz. precursor ratio, reaction temperature and duration were optimized. Nanostructured Bi2S3 synthesized at optimum conditions was further characterized by XRD, FESEM and FETEM, to study their phase, morphology and structure. The microscopic and XRD study reveals the formation of nanoplates like structures of orthorhombic Bi2S3. An attempt has been made to provide with a plausible growth mechanism as a function of reaction temperature and duration. In order to exploit the high 'aspect ratio' of the Bi2S3 nanoplates and explore its feasibility as potential electron source, field emission (FE) study has been performed at base pressure of ∼1 × 10−8 mbar. The results obtained herein reveal the morphology dependent FE behaviour of Bi2S3 nanoplates. The emitter comprised of Bi2S3 nanoplates synthesized at 180 °C showed better FE properties, lower turn-on field value, delivery of large emission current density (∼1670 µA/cm2 at 6.9 V/µm) and excellent emission current stability which are comparable to alike emitters due to semiconducting nanostructures. Highly crystalline nature and high aspect ratio of Bi2S3 nanoplates might be responsible for their good FE performance. These Bi2S3 nanostructures may have potential for applications in other optoelectronics devices.

Field Emission in Emerging Two-Dimensional and Topological Materials: A Perspective

Since the first field emission model or the well-known Fowler-Nordheim (FN) law was formulated about a century ago (in 1928), it remains an active topic to discover different aspects of field emission due to new materials and structures, geometrical effects, high current space charge effects, short pulse regime, and analytical models. Despite its simplicity, the original FN law, or its improvement, the Murphy-Good (MG) model remains as the important equations to characterize different field emitters. With the emergence of two-dimensional (2-D) materials such as graphene, transition-metal dichalcogenide (TMD) materials, and topological materials (such as topological insulators and semimetals) in the past two decades, new experiments and theoretical models are produced to study the validity of FN law and MG model on field emission from these quantum materials and to explore their applications as compact field emitters operating at low turn-on field. In this short perspective, after a very brief introduction of FN law and some recent (selected) improvements, we proceed to review the experimental works measuring field emission from the abovementioned quantum materials. The key performances, such as experimental growth methods, and emission characteristics, such as turn-on field, field enhancement factor, and field emission current density, are summarized and compared. During the discussion, we also highlight some recent models proposed to account for the effects of nonparabolic dispersion and topologically nontrivial bandstructures within these quantum materials. We suggest the importance of having consistent physics-based models to understand the field emission from these quantum materials and reinforce the presence of a non-FN scaling law due to their unique properties absent from the traditional bulk materials. Finally, we conclude by highlighting some possible new directions that may be further explored in future.

Tubular Diamond as an Efficient Electron Field Emitter

Herein, we present a straightforward and cost-effective procedure for producing conductive diamond tubes on the surface of porous carbon nanotube hollow fibers using successive 10-pulsed laser annealing shots and 6 h of hot filament chemical vapor deposition techniques. Room-temperature Raman and X-ray diffraction spectra reveal the signature T2g peaks near 1332.4 cm–1 and 111 planes of diamonds near 43.9°, respectively. A low turn-on field (ETO) ∼1.85 V/μm@1 μA/cm2 and a threshold field (ETH) ∼2.54 V/μm@10 μA/cm2 were observed for the tubular diamond structures. The field enhancement factor (β) was calculated at 3594 and highly stable field emission current stability was observed over a long period of 4 h. For the first time, a good insight into the field emission results of the diamond is established with the structural, electronic properties, and the work function (φ) ∼4.84 eV analysis conducted by the density functional theory simulation. Finite electronic states at the Fermi level are observed beyond a band gap, and it demonstrates the wide-band gap (4.4 eV) semiconducting nature of the diamond. The Bader charge analysis and maximum entropy method pattern revealed the negative electron affinity of the diamond, and it is responsible for the emission of electrons from the conduction band of the diamond. Besides, the accumulation of charge carriers, which contributes to the electric field emission, takes place due to the weak π bonds of carbon atoms. The low turn-on field, the high field enhancement factor, and the good field emission current stability of tubular diamond offer great prospects for future efficient and low-cost field emission devices.

Controllable modulation of patterned vertical graphene through macro-geometries for high current field emitters

In this work, in-situ growth of vertical graphene (VG) in controllable patterns was achieved through macro-geometric modulation of nickel substrates, followed by the adjustment of growth density and size of VG. When VG was grown in controllable patterns, the turn-on electric field decreased from 1.04 V/μm for initial VG to 0.69 V/μm and the current variation of patterned vertical graphene (PVG, 7%) was obviously lower than that of initial VG (23%). The outstanding field emission properties of PVG were essentially attributable to the weakening of field shielding. The COMSOL simulation demonstrated that PVG reduced field shielding and VG grown on Ni aggregation provided stronger contribution to field emission. In addition, structural stability of VG and connection between VG and substrate were observed in SEM and TEM. The results had implications in understanding the influence of structural stability on field emission properties by observing the cross section of VG-substrate and the nano-structure evolution of VG before and after field emission.

Improvement of the field emission lifetime of freestanding vertically aligned carbon nanotubes by coating with a metallic protective layer

In this article, we present a method to improve the field emission (FE) lifetime of freestanding vertically aligned carbon nanotubes (VACNTs) by uniformly coating the surface of VACNTs with a thin metallic layer that has low work function, high melting point and high electrical conductivity. The effects of three different metal shells on the FE performance are investigated. The FE performances of these VACNTs are evaluated by testing the turn-on electric field and long-term FE performance. The metal coatings do not have pronounced effects on turn-on electric field of VACNTs, but their FE lifetimes were improved to varying degrees. A 5 nm tungsten and gold coatings have the most significant improvement on the FE lifetime and current density stability. They have shown negligible degradation during continuous 48-h FE testing at a current density over 7 mSSA·cm −2. In addition, a 10 nm titanium, gold, and tungsten coatings also provide significant improvements in lifetime and emission current stability. Furthermore, it was observed that the metal shells are uniformly distributed on the surface of VACNTs, and they can effectively protect the VACNT from being melted by the Joule heat generated during FE. Therefore, metal-coated VACNTs have the potential to increase the lifetime of VACNT emitters during high current FE applications.

Growth and integration of aligned carbon nanotube-based field emission cathode for electron gun device-level fabrication

This study elucidates on growth and integration of aligned carbon nanotube-based field emission cathode for electron gun-device fabrication. Particularly, it emphasises on field emission (FE) and thermal transport (TT) properties of carbon nanotube (CNT) arrays with controlled atomistic defects (AD) to design a cold cathode (CC) for electron gun. To assess the influence of AD on FE and TT, aligned undoped (pure CNT) and N-doped herringbone (doped CNT) were fabricated using droplet-assisted solvent-thermolysis to use them as CC. Results demonstrated that doped CNT with higher degree of AD exhibited a lower turn-on field in FE in comparison to pure CNT could be ascribed to N addition in carbon lattice. Ambiguously, doping-mediated AD in doped CNT helps to achieve the best FE but lowers TT with significant decrease in thermal conductivity (111 to 5.1 W/m.k at room temperature) in comparison to pure CNT. Based on the FE behavior, a doped CNT arrays-based cathode was integrated into an electron gun, which exhibited maximum emission current of 81.3 mA/cm2 at a grid voltage of 2 kV.

Synthesis and Physical Characteristics of Undoped and Potassium-Doped Cubic Tungsten Trioxide Nanowires through Thermal Evaporation.

We report an efficient method to synthesize undoped and K-doped rare cubic tungsten trioxide nanowires through the thermal evaporation of WO3 powder without a catalyst. The WO3 nanowires are reproducible and stable with a low-cost growth process. The thermal evaporation processing was conducted in a three-zone horizontal tube furnace over a temperature range of 550-850 °C, where multiple substrates were placed at different temperature zones. The processing parameters, including pressure, temperature, type of gas, and flow rate, were varied and studied in terms of their influence on the morphology, aspect ratio and density of the nanowires. The morphologies of the products were observed with scanning electron microscopy. High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction studies were conducted to further identify the chemical composition, crystal structure and growth direction of the nanostructures. Additionally, the growth mechanism has been proposed. Furthermore, we investigated the potassium doping effect on the physical properties of the nanostructures. Photoluminescence measurements show that there were shorter emission bands at 360 nm and 410 nm. Field emission measurements show that the doping effect significantly reduced the turn-on electric field and increased the enhancement factor. Furthermore, as compared with related previous research, the K-doped WO3 nanowires synthesized in this study exhibited excellent field emission properties, including a superior field enhancement factor and turn-on electric field. The study reveals the potential of WO3 nanowires in promising applications for sensors, field emitters and light-emitting diodes.

Efficient field emission from ultrafine nanostructured lanthanum sulfide synthesized by chemical route

Lanthanum sulfide having a rocksalt structure has attracted lots of research interest because of its tremendous applications in the field of display devices, optoelectronic, field emission, and thermoelectric devices due to their low work function, and excellent chemical and physical properties. In the present work, we have synthesized LaS2 ultrafine nanostructures using anisotropic nanostructures of La(OH)3. The synthesis of anisotropic La(OH)3 has been attempted by the micellar-assisted hydrothermal route. The obtained La(OH)3 was further heated with elemental Sulfur at ambient pressure, leading to the stabilization of LaS2 of size ∼25 nm. Further, the as-obtained lanthanum disulfide was used for making LaS2 ink and spin-coated over a silicon substrate to fabricate LaS2 film. Field emission study of LaS2 film shows the lowest turn-on field (<3.9 V/μm), high field enhancement factor (β = 14,594), and high current density of 7.15 μA/cm2 has been obtained, which is around 10 times higher than earlier reports.

The effects of Ar + N2 plasma power-based attachment of metal nanoparticles on the electron field emission properties of carbon nanotubes

An ideal vacuum-based electron emitter requires a low turn-on field and quick emission processes. Carbon nanotubes (CNTs) have great potential for emission applications, but have some limitations that affect their performance. Consequently, they can benefit from the alteration of their surface morphology upon decoration with plasma-based metal nanoparticles. In this work, we have attached iron nanoparticles on the CNTs surface via a radio frequency (rf) sputtering process using Ar + N2 gas with various plasma power in steps of 50 W. Field emission scanning electron microscopy (FESEM) micrographs have confirmed the attachment of the iron nanoparticles and etching of the nanotubes surface at high plasma power. The Raman spectra strongly confirm the formation of defects in the carbon sheet of the nanotubes. In the plasma treatment process, the increase in the Dband intensity enhanced the degree of disorder and may be beneficial for enhanced emission properties. The field electron emission properties are significantly enhanced after the Fe nanoparticles attached with plasma incorporated in terms of the reduction in Eto (1.64 from 2.02 V/μm) &Eth (1.98 from 2.64 V/μm), and increase in J (391.11–1179.24 μA/cm2) and β (1419–2900), respectively. The field emission parameters of the field emitters are modified due to incorporation of nitrogen species, attached Fe nanoparticles, and reduction in the nanotube density. The as-prepared field emitters also qualified the orthodox field emission hypothesis test by exhibiting fextr values in an acceptable range. Therefore, we can use the Ar + N2 plasma-based Fe nanoparticles decorated CNT field emitters in vacuum electronic device applications.

Electrical and magnetic performances of semiconductor based carbon nanoparticles

The temperature-dependent resistivity, room temperature electron field emission, and magnetic performance within the temperature range of 2–300 K of previously chemically synthesized pure carbon nanoparticles (CNPs) from candle soot having particle sizes of ≈2–6 nm have been studied. The highest saturation magnetization and coercivity of ≈8.9 × 10−2 emu/g and ≈130.8 Oe were obtained at 2 and 4 K, respectively. We also determined that the turn-on electric field is ≈27 V/μm with a current density of ≈0.8 × 10−8 A/cm2 @ 20 V/μm. The temperature vs electrical resistivity and applied high electric field (EA) vs electron emission show the tunneling from one conductive sp2 C=C cluster to another separated by an sp2 C=C cluster (and/or an insulating sp3 C–C cluster). The magnetic, as well as the electric, field emission results imply that CNPs could be useful for the fabrication of spintronic as well as field-emission display devices.

Thickness dependent field emission study of LaB6 coated Si nanowire arrays

A simple physical metal mask is efficiently employed to obtain an array of silicon (Si) nanowires (Si-NWs) on a Si substrate grown using the hot filament chemical vapor deposition route. Well adhered and uniform coating of different thicknesses (20 and 50 nm) of lanthanum hexaboride (LaB6) on Si-NWs was obtained using electron beam evaporation technique. The thickness of LaB6 coating was estimated from ellipsometry measurement. Structural, morphological, and chemical properties of the LaB6 coated Si-NWs (LaB6@Si-NWs) arrays were revealed using x-ray diffraction, field emission scanning electron microscope, transmission electron microscope, Raman spectroscopy, and x-ray photoelectron spectroscopy. Field electron emission characteristics of pristine Si-NW array and LaB6 coated Si-NWs array emitters were studied in planar diode configuration at a base pressure of 1 × 10−8 mbar. The values of turn-on field (current density ∼1 μA/cm2) were observed as ∼2.2, 1.2, and 1.6 V/μm for pristine Si-NWs, LaB6@Si-NWs_20, and LaB6@Si-NWs_50 array emitters, respectively. Furthermore, maximum emission current densities of ∼1276.81, 2763.64, and 2231.81 μA/cm2 have been extracted from the pristine Si-NWs, LaB6@Si-NWS_20, and LaB6@Si-NWS_50 array emitters at an applied field of 3.1, 2.7, and 2.7 V/μm, respectively. The LaB6@Si-NWS_20 array emitter demonstrated superior FEE properties as compared to the pristine Si-NWs and LaB6@Si-NWS_50 emitters. Furthermore, LaB6@Si-NWS_20 emitter depicted very good emission current stability tested at a preset value of 1 μA over a duration of 3 h. The enhanced FEE performance exhibited by the LaB6@Si-NWs_20 array emitter is attributed to reduction in effective work function and enhanced electron tunneling probability across the LaB6–Si interface.