Similarities in the 'cold' electron emission characteristics of diamond coated molybdenum electrodes and polished bulk graphite surfaces

Xu, Ning; Tzeng, Yonhua; Latham, R.V.

doi:10.1088/0022-3727/26/10/035

Cited by 249 publications

(72 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[1][2][3][4] Initial interest was stimulated by the prospect of electron emission at very low electric fields due to the low electron affinity of the carbon in the diamond form when terminated with hydrogen: the diamond surface, in fact, has a negative electron affinity ͑NEA͒. Various carbon based cold cathodes including diamond, 5 nanodiamond, 6 diamondlike carbon ͑DLC͒ and tetrahedral amorphous carbon, 7,8 carbon nanotubes, 9,10 and nanoclustered carbon [11][12][13][14] have all been shown to emit electrons at reasonably low electric fields.…”

Section: Introductionmentioning

confidence: 99%

Field emission from as grown and nitrogen incorporated tetrahedral amorphous carbon/silicon heterojunctions grown using a pulsed filtered cathodic vacuum arc technique

Panwar

Rupesinghe

Amaratunga

2008

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

View full text Add to dashboard Cite

This article reports the field emission measurements on as grown tetrahedral amorphous carbon ͑ta-C͒ and nitrogen incorporated tetrahedral amorphous carbon ͑ta-C: N͒ films grown using a pulsed filtered cathodic vacuum arc technique. The effect of varying thickness on field emission in the as grown ta-C films and the effect of varying nitrogen content in ta-C: N films have also been studied. The values of threshold field of emission ͑E turn on ͒ increase with decrease of thickness in the as grown ta-C films. Nitrogen incorporation up to 5.2 at. % in ta-C films decreases the value of E turn on from 9.9 to 5.1 V / m and thereafter it starts increasing again. To understand the mechanism of electron emission, a realistic energy band diagram of ta-C : N / n ++ Si heterojunction has been proposed from the experimentally measured valence and conduction band offsets, using in situ x-ray photoelectron spectroscopy and optical spectroscopy data already published in DRM 9 ͑2000͒ 1148. The data are explained using the Fowler and Nordheim theory. The field emission results obtained reveal that there exists a barrier to emission and the main barrier is at the front surface and this is related to the conduction band offset of the ta-C : N / n ++ Si heterojunction.

show abstract

Section: Introductionmentioning

confidence: 99%

Field emission from as grown and nitrogen incorporated tetrahedral amorphous carbon/silicon heterojunctions grown using a pulsed filtered cathodic vacuum arc technique

Panwar

Rupesinghe

Amaratunga

2008

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

View full text Add to dashboard Cite

show abstract

“…The experimentally observed current-voltage relation fits the Fowler-Nordheim expression (Eq. 4) corresponding to tunneling through a barrier [20).…”

Section: Cold Cathode Electron Emissionmentioning

confidence: 99%

“…The effective work function and emission area can be determined from the slope and intercept, respectively, of a plot of ln(J/E2) vs l/E, assuming a known value of~. The value of the effective work function tends to be quite low [26], typically less than 0.1 eV, and the emission comes from isolated, discrete sites [20] which are often very low in density. It has been demonstrated via ultra-violet photoelectron spectroscopy [20,27] that under certain circumstances, diamond is a negative electron affinity (NEA) material (i. e., the bottom of the conduction band lies above the vacuum level) with a 5.5 eV band gap.…”

Section: Cold Cathode Electron Emissionmentioning

confidence: 99%

“…It is not clear at this point what role NEA has in the electron emission process in diamond and diamond-like carbon films. If the barrier is at the diamond-vacuum interface, then damage may be required simply to provide conductive paths through the film, although XU, Tzeng, and Latham [20] argue that such conducting paths are inconsistent with the observed low density of emitting sites. They have proposed a model in which the intergranular regions of graphite which typically form beh.veen diamond grains act as antennas which give rise to a local field enhancement sufficient to form conducting channels within the diamond matrix.…”

Section: Cold Cathode Electron Emissionmentioning

confidence: 99%

See 1 more Smart Citation

Morphology and Electron Emission Properties of Nanocrystalline CVD Diamond Thin Films

et al. 1997

View full text Add to dashboard Cite

Nanocrystalline diamond thin films have been produced by microwave plasma-enhanced chemical vapor deposition (MPECVD) using C60/Ar/H2 or CH4/Ar/H2 plasmas. Films grown with H2 concentration ≤ 20% are nanocrystalline, with atomically abrupt grain boundaries and without observable graphitic or amorphous carbon phases. The growth and morphology of these films are controlled via a high nucleation rate resulting from low hydrogen concentration in the plasma. Initial growth is in the form of diamond, which is the thermodynamic equilibrium phase for grains < 5 nm in diameter. Once formed, the diamond phase persists for grains up to at least 15–20 nm in diameter. The renucleation rate in the near-absence of atomic hydrogen is very high (∼1010 cm2sec−1), limiting the average grain size to a nearly constant value as the film thickness increases, although the average grain size increases as hydrogen is added to the plasma. For hydrogen concentrations less than ∼20%, the growth species is believed to be the carbon dimer, C2, rather than the CH3* growth species associated with diamond film growth at higher hydrogen concentrations. For very thin films grown from the C60 precursor, the threshold field (2 to ∼60 volts/micron) for cold cathode electron emission depends on the electrical conductivity and on the surface topography, which in turn depends on the hydrogen concentration in the plasma. A model of electron emission, based on quantum well effects at the grain boundaries is presented. This model predicts promotion of the electrons at the grain boundary to the conduction band of diamond for a grain boundary width ∼3–4 Å, a value within the range observed by TEM.

show abstract

“…A number of research groups have shown experimental results in which the electron emission from polycrystalline diamond and diamond like carbon ͑DLC͒ ͑or amorphous carbon͒ has been achieved at low threshold fields. [2][3][4][5][6][7] In this article we will develop a model that can be used to explain the observed electron emission characteristics of polycrystalline diamond using a model which involves the presence of DLC ͑or amorphous carbon͒ at/in the grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the electron field emission process in polycrystalline diamond and diamond-like carbon thin films

Silva¹,

Amaratunga²,

Okano³

1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

View full text Add to dashboard Cite

Electron field emission has been observed from carbon thin films at relatively low electric fields. These films range from amorphous carbon to polycrystalline diamond films. There are many models that attempt to account for the electron field emission process observed in these films. The initial models that were based on the emission due purely to a negative electron affinity have now been modified. The emission from diamond like carbon ͑DLC͒ films, although following a FowlerNordheim type curve, do not give realistic values for the emission areas or barriers purely based on a tunneling mechanism. Therefore, a model based on space charge band bending at the back junction is proposed to account for the electron emission at low electric fields from DLC. In this ''space charge interlayer'' model the real cathode is the substrate, from which hot electrons are created due to the fully depleted DLC film the electrons encounter before reaching the front surface of the film. In this article we extend the model to incorporate the emission of electrons from polycrystalline diamond thin films.

show abstract

Similarities in the 'cold' electron emission characteristics of diamond coated molybdenum electrodes and polished bulk graphite surfaces

Cited by 249 publications

References 9 publications

Field emission from as grown and nitrogen incorporated tetrahedral amorphous carbon/silicon heterojunctions grown using a pulsed filtered cathodic vacuum arc technique

Field emission from as grown and nitrogen incorporated tetrahedral amorphous carbon/silicon heterojunctions grown using a pulsed filtered cathodic vacuum arc technique

Morphology and Electron Emission Properties of Nanocrystalline CVD Diamond Thin Films

Modeling of the electron field emission process in polycrystalline diamond and diamond-like carbon thin films

Contact Info

Product

Resources

About