Photoemission from the negative electron affinity (100) natural hydrogen terminated diamond surface

Diederich, L.; Küttel, O. M.; Schaller, E.; Schlapbach, L.

doi:10.1016/0039-6028(95)01117-x

Cited by 65 publications

(43 citation statements)

References 22 publications

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“…VBM−E F ). The determined energy disthat for the (111) surface we should not measure photoelectrons at low kinetic energies in order to tance VBM−E F is in agreement with earlier He II measurements [4]. The determination of the VBM satisfy the conservation of the parallel wave vector component (k || ) in photoemission discussed below.…”

Section: Resultssupporting

confidence: 62%

“…In this work we present an investigation of the surface presents a (2×1) reconstruction as shown by the low energy electron diffraction (LEED) NEA peak as well as quantitative NEA values of the different terminated and oriented diamond pattern [4,17] and by the atomic resolution scanning tunneling microscopy (STM ) images [6,20]. surfaces.…”

Section: Introductionmentioning

confidence: 99%

“…The surfaces present no surface contamination sufficient to be ejected into vacuum. For a better understanding of the emission process and its ( less then 0.5 at.% of oxygen which is the detection limit of the technique) as shown by the MgKa optimization for the synthesis of thin diamond films, the exact determination of the NEA peak as X-ray photoelectron normal emission overview spectrum [4,18,19]. Even after several weeks expowell as the NEA value as a function of surface termination and surface orientation are of prime sure to air, the surfaces present no surface contamination.…”

Section: Introductionmentioning

confidence: 99%

“…However, the diamond [7][8][9][10], or as a surface channel field-effect transis-(100), (110) and (111) surfaces are known to tor [11,12]. The diamond-based devices show even exhibit a negative electron affinity (NEA) when better characteristics owing to a hydrogen terterminated with hydrogen [1][2][3][4][5][6]. NEA is defined mination, inducing a NEA behavior [13][14][15] if the vacuum level E vac lies below the conduction Field-emission measurements [8][9][10] on nitrogenband minimum (CBM ) at the surface and, hence, doped diamond show threshold fields less than 0.5 V mm−1.…”

Section: Introductionmentioning

confidence: 99%

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NEA peak of the differently terminated and oriented diamond surfaces

et al. 1999

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The negative electron affinity (NEA) peak of differently terminated and oriented diamond surfaces is investigated by means of ultraviolet photoemission spectroscopy. Electron emission measurements in the range below the conduction band minimum (CBM ) up to the vacuum level E vac permit the quantitative calculation of the upper limit of the NEA value. The inelastic scattering at the surface to the vacuum interface and the emission of electrons from the unoccupied surface states, situated in the band gap, are the mechanisms responsible for explaining this below CBM emission. All the H-terminated diamond surfaces present NEA. However, the characteristic NEA peak observed in the spectra is only detected for the (100)-(2×1):H surface and to a lesser extent for the (110)-(1×1):H surface, while it is absent for the (111)-(1×1):H surface because of the k || -conservation in the photoemission process.

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Section: Resultssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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NEA peak of the differently terminated and oriented diamond surfaces

et al. 1999

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“…The calculations were substantiated by experiment on a practically hydrogen-free boron doped type IIb (100) diamond surface that exhibited a positive electron affinity of 0.5 eV (Diederich et al, 1996). Similarly, for a clean nitrogen-doped type Ib (100) diamond surface, a positive electron affinity of 0.5 ± 0.1 eV was reported from photoelectron emission spectroscopy (Diederich et al, 1998b).…”

Section: Single-crystal Phosphorus-doped Diamondmentioning

confidence: 65%

Advances in Thermionic Energy Conversion through Single-Crystal n-Type Diamond

Koeck

Nemanich

2017

Front. Mech. Eng.

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Thermionic energy conversion, a process that allows direct transformation of thermal to electrical energy, presents a means of efficient electrical power generation as the hot and cold side of the corresponding heat engine are separated by a vacuum gap. Conversion efficiencies approaching those of the Carnot cycle are possible if material parameters of the active elements at the converter, i.e., electron emitter or cathode and collector or anode, are optimized for operation in the desired temperature range. These parameters can be defined through the law of Richardson-Dushman that quantifies the ability of a material to release an electron current at a certain temperature as a function of the emission barrier or work function and the emission or Richardson constant. Engineering materials to defined parameter values presents the key challenge in constructing practical thermionic converters. The elevated temperature regime of operation presents a constraint that eliminates most semiconductors and identifies diamond, a wide band-gap semiconductor, as a suitable thermionic material through its unique material properties. For its surface, a configuration can be established, the negative electron affinity, that shifts the vacuum level below the conduction band minimum eliminating the surface barrier for electron emission. In addition, its ability to accept impurities as donor states allows materials engineering to control the work function and the emission constant. Singlecrystal diamond electrodes with nitrogen levels at 1.7 eV and phosphorus levels at 0.6 eV were prepared by plasma-enhanced chemical vapor deposition where the work function was controlled from 2.88 to 0.67 eV, one of the lowest thermionic work functions reported. This work function range was achieved through control of the doping concentration where a relation to the amount of band bending emerged. Upward band bending that contributed to the work function was attributed to surface states where lower doped homoepitaxial films exhibited a surface state density of ∼3 × 10 11 cm −2 . With these optimized doped diamond electrodes, highly efficient thermionic converters are feasible with a Schottky barrier at the diamond collector contact mitigated through operation at elevated temperatures.

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Chemical Bonding of Fullerene and Fluorinated Fullerene on Bare and Hydrogenated Diamond

Ouyang

Wee

et al. 2008

ChemPhysChem

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We investigate the interface between a C(60) fullerite film, C(60)F(36), and diamond (100) by using core-level photoemission spectroscopy, cyclic voltammetry (CV), and high-resolution electron energy loss spectroscopy (HREELS). We show that C(60) can be covalently bonded to reconstructed C(100)-2x1 and that the bonded interface is sufficiently robust to exhibit characteristic C(60) redox peaks in solution. The bare diamond surface can be passivated against oxidation and hydrogenation by covalently bound C(60). However, C(60)F(36) is not as stable as C(60) and desorbs below 300 degrees C (the latter species being stable up to 500 degrees C on the diamond surface). Neither C(60) fullerite nor C(60)F(36) form reactive interfaces on the hydrogenated surface-they both desorb below 300 degrees C. The surface transfer doping process of hydrogenated diamond by C(60)F(36) is the most evident one among all the adsorbate systems studied (with a coverage-dependent band bending induced by C(60)F(36)).

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Photoemission from the negative electron affinity (100) natural hydrogen terminated diamond surface

Cited by 65 publications

References 22 publications

NEA peak of the differently terminated and oriented diamond surfaces

NEA peak of the differently terminated and oriented diamond surfaces

Advances in Thermionic Energy Conversion through Single-Crystal n-Type Diamond

Chemical Bonding of Fullerene and Fluorinated Fullerene on Bare and Hydrogenated Diamond

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