Vacuum arc discharges preceding high electron field emission from carbon films

Gröning, Oliver; Küttel, O. M.; Schaller, E.; Gröning, P.; Schlapbach, L.

doi:10.1063/1.118145

Cited by 101 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results are in good agreement with the observations of Groning et al, 9 Talin et al, 10 and Coll et al, 4 but differ from those obtained, for example, by Satyanarayana et al 8 However, the latter used the parallel-plate anode geometry in their experiments. This method has a drawback of ''picking up'' the hottest spot on the sample, and therefore, provides no reliable information about the average FE properties of the material over large surface areas.…”

supporting

confidence: 90%

Field-emission studies of smooth and nanostructured carbon films

Merkulov

Lowndes

Baylor

1999

Applied Physics Letters

View full text Add to dashboard Cite

Electron field-emission measurements of carbon films prepared by pulsed-laser deposition (PLD) and hot-filament chemical-vapor deposition (HF-CVD) are reported. Smooth PLD carbon films, with both high- and low-sp3 contents, appear to be poor field emitters. In contrast, HF-CVD carbon exhibits very good field-emission properties, including the emission turn-on field as low as 9 V/μm, high emission site density, and excellent durability. In addition, HF-CVD was carried out at temperatures below 600 °C, compatible with the use of glass substrates. The promising field-emission properties of HF-CVD carbon are attributed to the nanostructured nature of this material.

show abstract

supporting

confidence: 90%

Field-emission studies of smooth and nanostructured carbon films

Merkulov

Lowndes

Baylor

1999

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…From these characterizations it is revealed that in general these films are inhomogeneous in structure, nanocrystalline in nature and have a distribution of carbon clusters confined to a nanometer size range. Contrary to what would be expected from the microprotrusion model of EFE, 23 the relatively smoother surfaces give the lowest turn-on field. Though it is believed that small grain sizes produce similar field enhancement effects like the sharp protruding structures, as has been argued by Chen et al 43 and Rouse et al, 44 but in view of these small grain size values, it may also be presumed that there is a network of grain boundaries and a higher level of nondiamond carbon ͑sp 2 C͒ components, which can increase the conductivity and assist in lowering the threshold field.…”

Section: Resultscontrasting

confidence: 79%

“…In spite of the fact that the original work on electron field emission from diamond was motivated by the discovery of its negative electron affinity ͑NEA͒, 22 the ease of emission from many carbon materials suggests that the NEA is not a prerequisite and may be a bonus feature. Besides the existence of several propositions such as microprotrusion on the emitting surface, 23 electron injection into the diamond conduction band from cathode electrode, 24 surface termination, 25 depletion layers, 25 film thickness, 25 impurity elements and subbands, 26 and controlling the microstructure in terms of sp 2 -bonded carbon phase ͑sp 2 C͒ as here. 25 Because of the paucity of a single definite source of electron emission, it defies our understanding of the EFE mechanism since no clear consensus has been yet established and remains elusive and divergent.…”

Section: Investigations Of the Electron Field Emission Properties Andmentioning

confidence: 99%

Investigations of the electron field emission properties and microstructure correlation in sulfur-incorporated nanocrystalline carbon thin films

Gupta

Weiner

Morell

2002

Journal of Applied Physics

View full text Add to dashboard Cite

Role of sp 2 C cluster size on the field emission properties of sulfur-incorporated nanocomposite carbon thin films Appl.Results are reported on the electron field emission properties of sulfur ͑S͒-incorporated nanocrystalline carbon (n-C:S) thin films grown on molybdenum ͑Mo͒ substrates by hot-filament chemical vapor deposition ͑HFCVD͒ technique. In addition to the conventionally used methane (CH 4 ) as carbon precursor with high hydrogen (H 2 ) dilution, hydrogen sulfide-hydrogen (H 2 S)/H 2 premix gas was used for sulfur incorporation. The field emission properties for the S-incorporated films were investigated systematically as a function of substrate temperature (T S ) and sulfur concentration. Lowest turn-on field achieved was observed at around 4.0 V/m for the n-C:S sample grown at T S of 900°C with 500 ppm of H 2 S. These results are compared with those films grown without sulfur (n-C) at a particular T S . The turn-on field was found to be almost half for the S-assisted film thus demonstrating the effect of sulfur addition to the chemical vapor deposition process. An inverse relation between turn-on field (E C ), growth temperature and sulfur concentration was found. The S incorporation also causes significant microstructural changes, as characterized with non-destructive complementary ex situ techniques: scanning electron microscopy ͑SEM͒, atomic force microscopy ͑AFM͒, and Raman spectroscopy ͑RS͒. S-assisted films show relatively smoother and finer-grained surfaces than those grown without it. These findings are discussed in terms of the dual role of sulfur in enhancing the field emission properties by controlling the sp 2 C cluster size and introducing substantial structural defects through its incorporation. The in-plane correlation length (L a ) of sp 2 C cluster was determined from the intensity ratio of the Dand G-bands ͓I(D)/I(G)͔ in the visible RS as a function of deposition temperature and sulfur concentration using a phenomenological model. The turn-on field was found to decrease with increasing sp 2 C cluster size in general ranging from 0.8 to 1.4 nm. The films having sp 2 C clusters of around 1.4 nm had the lowest turn-on field and steep rising emission currents, providing an estimate of optimum size for L a for the material grown hereby. These findings are assessed in terms of a reduced field emission barrier brought about by the sulfur addition and the need for relatively longer conductive paths capable of withstanding the relatively large emission currents. It is because the sp 2 C cluster size predominate the chemical environment, chemical order, sp 3 content or local conductivity. Besides, although most of the S is expected to be electrically inactive, under the high doping conditions ͑larger S/C͒ hereby employed, there may be some amount of S in donor states, an indication of the availability of conduction electrons. These results also suggest that the behaviors of sulfur-incorporated nanocrystalline carbon thin films are closer to that grown with phosphorus ͑P͒ and Nitrogen ͑N͒ eleme...

show abstract

“…By biasing the sample to a negative potential ͑Keithley 237͒ while keeping the grid at ground, electron field emission occurs and the energy of the electrons are measured with the hemispherical energy analyzer of the spectrometer. 27 All measurements were performed at a pressure below 10 Ϫ9 mbar. The sample can be rotated in an azimuthal as well as in a polar direction for x-ray photoelectron diffraction.…”

Section: Methodsmentioning

confidence: 99%

Surface conductivity induced electron field emission from an indium cluster sitting on a diamond surface

Küttel

Gröening

1998

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

Self Cite

View full text Add to dashboard Cite

Electron field emission has been performed from a 5 μm indium cluster sitting on a nitrogen doped diamond (100) surface (3×3×1 mm3). The motivation to study such a system arose from the fact that electron field emission from N-doped diamond was reported in literature. However, the emission mechanism is not really known and still the subject of an intense discussion in the diamond/amorphous carbon community. We have chosen this setup to conduct a model experiment with well-defined parameters. The emission properties were analyzed by energy resolved field emission (FEED). We found that electron emission takes place at the apex of the indium grain for a hydrogenated diamond surface. However, large energy shifts were observed in the FEED spectra due to a potential drop across the hydrogen saturated surface. An oxygen termination kills the emission. By sputtering the surface the emission reappears with much lower energy shifts in the FEED spectra due to the conductive sp2 layer. We present a model taking into account the ohmic surface resistivity of the diamond surface and discuss the impact on emission properties of nanoclustered films. The results presented in this article show that surface conduction (hydrogen terminated or sputtered surface) can lead to electron field emission with large shifts in the FEED spectra. While the emission stems from a metallic micron sized tip, the electron supply is guaranteed by surface conduction.

show abstract

Vacuum arc discharges preceding high electron field emission from carbon films

Cited by 101 publications

References 0 publications

Field-emission studies of smooth and nanostructured carbon films

Field-emission studies of smooth and nanostructured carbon films

Investigations of the electron field emission properties and microstructure correlation in sulfur-incorporated nanocrystalline carbon thin films

Surface conductivity induced electron field emission from an indium cluster sitting on a diamond surface

Contact Info

Product

Resources

About