Characterization of thin film electron emitters by scanning anode field emission microscopy

Nilsson, L.; Gröening, O.; Groening, P.; Kuettel, O.M.; Schlapbach, L.

doi:10.1063/1.1379559

Cited by 89 publications

(49 citation statements)

References 34 publications

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“…This superiority may profit from two factors. Firstly, Bonard and Nilsson have pointed out that only a small proportion of emitters contribute to the current in FE of arrays [23,24]. In our cases, only the nanopencils near the apex of the pyramids contributed to the emission current since they are closer to the anode and the field screening effect among apices is weak due to large separation [12,25].…”

Section: Resultsmentioning

confidence: 72%

Enhanced field emission from ZnO nanopencils by using pyramidal Si(100) substrates

Xiao

Zhang

et al. 2008

Applied Surface Science

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Section: Resultsmentioning

confidence: 72%

Enhanced field emission from ZnO nanopencils by using pyramidal Si(100) substrates

Xiao

Zhang

et al. 2008

Applied Surface Science

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“…[7,12] Therefore the only realistic presentation of I-V behaviors was gathering the data by a numbers of experiments. Of course this is even not a complete approach to analyze the field emission sites with increasing the applied current and/or voltages.…”

Section: Fig 3 Typical Field Emission I-v Curves Of the Ni Nio Coamentioning

confidence: 99%

Enhanced Field‐Emission Obtained from NiO Coated Carbon Nanotubes

Yang¹,

Park²,

Cho³

2007

Adv Eng Mater

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Carbon nanotubes(CNTs) have drawn much interests because of their unique electrical, mechanical properties and their potential applications in field emission displays, sensors, transistors, nano-tweezers and AFM tips. [1][2][3][4] Above all, the field emission from CNTs have been extensively studied due to the nanometer-size diameter, structural integrity, high electrical conductivity and chemical stability after first demonstration in 1995. [5] According to Fowler-Nordheim's theory the FE current density (J) is a function of the electric field E and the work function f of emitter. [6,7] For metal, with typical work function and a flat surface the threshold field is typically around 10 4 V/lm, but it can be easily generated by the field-enhancing properties of tip-like structures such as CNT. All the field emission sources rely on the field enhancement originated from the apex of a needle of height and radius. A CNT with a diameter of 10 nm and a length of 2 lm was reported to exhibit a field-enhancement factor (b) up to 400 which is equal to the ratio of height/radius and the field emission from CNTs can be generated at the apex of CNT by a very low applied field of 7.5 V/lm.In advances in research, the enhancement of the fieldemission properties was achieved by coating the emitter's tip with wide band gap materials (WBGM). Accordingly LiF, [8] CaF 2,[9] AlN [10] and c-BN [11] were applied to metal emitters to decrease the effective work function of emitters, which correspondingly increases emissivity and also MgO and SiO 2 were applied to CNT emitters. [13,14] Such a coating gives excellent emission characteristics and protection from adsorption or ion bombardment of residual gas molecules in the vacuum cavities such as display panel or field-emission lamps.In this communication, we introduce NiO coated CNT emitters for enhancing the field-emission properties in terms of electron emissivity and structure stability protective from residual gas and corrosive environment as well. Since the field emission lighting devices comprise a planar substrate with arrays or bundle of emitters (cathode) and a phosphor coated display screen (anode) that is mounted in a parallel with the cathode plate for the electron bombardment from emitters.The both cathode and anode plates are assembled with micron scale spacers in between and sealed using frit glass under high vacuum grade. The pressure inside the device panel would be 10 -6 ∼ 10 -5 Torr. The inside pressure will be always degraded by the residual gas evaporating from the inner walls of phosphor layer during device operation. Besides the ion arcing from residual gas will deteriorate the emitting CNT tips resulting in a critical reduction of brightness. The authors developed CNTs coated all around with NiO in nanoscale aiming at the enhanced field-emission and environmental inertness for long life of electron emitter. The coating of NiO around CNTs was possible employing an electroless plating technique. Figure 1 shows the X-ray diffraction pattern of multiwall(MW) CNTs as-...

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“…[39] As a very high density of one-dimensional nanowires is often harmful to field electron emission because of the screen effects, [40,41] we have attempted the following experiments to control the density of the vertically aligned boron nanowires at the optimized theoretical values [42,43] to decrease the E on and E thres values. The inset of Figure 6 is the FN plot of the film of aligned BNWs.…”

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confidence: 99%

Fabrication of Vertically Aligned Single‐Crystalline Boron Nanowire Arrays and Investigation of Their Field‐Emission Behavior

et al. 2008

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Elemental boron arouses great interest from both scientific and technological areas of research because it has unique chemical and physical properties and its theoretical tubular structures may have higher electrical conductivity than carbon nanotubes. [1][2][3][4][5][6][7] High conductivity and chemical stability of boron or boride nanostructures have made it an attractive candidate for future applications in ideal cold-cathode materials, high-temperature semiconductor devices, or fieldeffect transistors. [8][9][10][11][12][13][14] In particular, for the application of field emission (FE), it is especially useful to synthesize large, vertical arrays of boron nanowires (BNWs) with the desired surface work function and FE behavior. So far, to our knowledge, while both amorphous [15][16][17][18][19][20] and crystalline boron nanowires [21,22] have been fabricated by magnetron sputtering, laser ablation, or chemical vapor methods, vertical arrays of single-crystal boron nanowires over a large area have not been synthesized in a one-step process. In addition, little attention [23][24][25] has been paid to the measurements of the physical properties of an individual boron nanowire. In this Communication, we report the successful synthesis of high-density, vertically aligned single-crystal boron nanowire arrays with a nanowire diameter of approximately 20-40 nm by a thermal carbon-reduction method. Moreover, we have measured the FE behavior and surface work function of a single boron nanowire, which is critical to evaluate the possibility of using boron nanowires as field-emission materials. For the purpose of better understanding the field-emission mechanism of a boron nanowire, the field-emission properties of a BNW film are also measured to compare with those of an individual nanowire. Figure 1 shows large-scale boron nanowire arrays on a Si(001) substrate after approximately 2-4 h of growth. As shown in Figure 1A, the high-density arrays are aligned vertically on the silicon substrate. Figure 1B is the highresolution scanning electron microscopy (SEM) image of the aligned BNWs, in which one can see that the length of the BNW is about 5 mm and the morphology of the nanowires is uniform. The aspect ratio of each boron nanowire is about 200, which is high enough for a field-emission application. The side and top views of the boron nanowire are shown in Figure 1C and D, respectively, which reveals the detailed morphology of the BNWs. The boron nanowires have a diameter of about 20-40 nm and no catalyst is found at their tip. The catalysts, however, were found to lie on the substrate arbitrarily when we peeled off some nanowire film from the substrate, as shown in Figure 1C. Thus, we believe that the growth is through a vapor-liquid-solid (VLS) mechanism and the binding force between the Fe 3 O 4 catalyst and the silicon substrate is strong. This strong binding leads to good conductivity between the boron nanowires and the substrate, which may contribute to their good field-emission properties. The alignment of BNWs can...

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Characterization of thin film electron emitters by scanning anode field emission microscopy

Cited by 89 publications

References 34 publications

Enhanced field emission from ZnO nanopencils by using pyramidal Si(100) substrates

Enhanced field emission from ZnO nanopencils by using pyramidal Si(100) substrates

Enhanced Field‐Emission Obtained from NiO Coated Carbon Nanotubes

Fabrication of Vertically Aligned Single‐Crystalline Boron Nanowire Arrays and Investigation of Their Field‐Emission Behavior

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