C<i>1s</i>excitation studies of diamond (111). II. Unoccupied surface states

Morar, J. F.; Himpsel, F. J.; Hollinger, G.; Jordon, J. L.; Hughes, G.; McFeely, F. R.

doi:10.1103/physrevb.33.1346

Cited by 133 publications

(63 citation statements)

References 35 publications

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“…They show a strong dispersion along the chain direction and are almost flat perpendicularly to it [71,75], consistently with a reconstruction model exhibiting one dimensional structures like the π bonded chains. There are also evidences of unoccupied surface states within the fundamental gap from two-photons photoelectron spectroscopy (2PPES) [84], high resolution soft X-rays absorption spectra [85], and electron energy loss spectroscopy (EELS) [81]. Finally a recently measured reflectance anisotropy spectrum [86,87] shows an optical gap between surface states of ∼ 1.5 eV.…”

Section: Electronic Band Structurementioning

confidence: 99%

The fascinating physics of carbon surfaces: first-principles study of hydrogen on C(0 0 1), C(1 1 1) and graphene

Marsili¹,

Pulci²

2010

J. Phys. D: Appl. Phys.

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Abstract.With the aid of ab-initio, parameter free calculations based on densityfunctional and many-body perturbation theory, we investigate the electronic band structure and electron affinity of diamond surfaces. We focus on clean, ideal (001) and (111) surfaces, and on the effect of hydrogen adsorption. Also single sheets of graphane, that is graphene functionalized upon hydrogen, are investigated. At full H-coverage nearly-free electron states appear near the conduction band minimum in all the systems under study. At the same time, the electron affinity is strongly reduced becoming negative for the hydrogenated diamond surfaces, and almost zero in graphane. The effects of quasi-particle corrections on the electron affinity and on the nearly free electron states are discussed.Confidential: not for distribution.

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Section: Electronic Band Structurementioning

confidence: 99%

The fascinating physics of carbon surfaces: first-principles study of hydrogen on C(0 0 1), C(1 1 1) and graphene

Marsili¹,

Pulci²

2010

J. Phys. D: Appl. Phys.

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“…The former is assigned to the unoccupied π * bond, which is characteristic of the sp 2 C=C bond. 28 The latter is due to σ * bond, which is characteristic of the sp 3 tetrahedral C-C bond. 29 The peak at ∼289.5 eV corresponds to the diamond core exciton, which is the result of the bound electron-hole pair.…”

Section: A the Overall Au-ion Irradiation Effectmentioning

confidence: 99%

The potential application of ultra-nanocrystalline diamond films for heavy ion irradiation detection

Chen

Wang

et al. 2013

AIP Advances

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The potential of utilizing the ultra-nanocrystalline (UNCD) films for detecting the Au-ion irradiation was investigated. When the fluence for Au-ion irradiation is lower than the critical value (fc = 5.0 × 1012 ions/cm2) the turn-on field for electron field emission (EFE) process of the UNCD films decreased systematically with the increase in fluence that is correlated with the increase in sp2-bonded phase (π*-band in EELS) due to the Au-ion irradiation. The EFE properties changed irregularly, when the fluence for Au-ion irradiation exceeds this critical value. The transmission electron microscopic microstructural examinations, in conjunction with EELS spectroscopic studies, reveal that the structural change preferentially occurred in the diamond-to-Si interface for the samples experienced over critical fluence of Au-ion irradiation, viz. the crystalline SiC phase was induced in the interfacial region and the thickness of the interface decreased. These observations implied that the UNCD films could be used as irradiation detectors when the fluence for Au-ion irradiation does not exceed such a critical value

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“…34 The monochromator energy scale was calibrated using the C1s → π* transition of graphite, located at 285.35eV. 35 The effects of incident beam intensity fluctuations and monochromator absorption features were eliminated by normalizing all NEXAFS spectra to the signal from a pure gold (gold deposited in situ) mesh (I 0 ). Partial electron yield (PEY) was monitored by a channeltron electron multiplier with an adjustable entrance grid bias (EGB).…”

Section: Near Edge X-ray Absorption Fine Structure (Nexafs)mentioning

confidence: 99%

Structure and DNA Hybridization Properties of Mixed Nucleic Acid/Maleimide−Ethylene Glycol Monolayers

et al. 2007

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The surface structure and DNA hybridization performance of thiolated single-strand DNA (HSssDNA) covalently attached to a maleimide-ethylene glycol disulfide (MEG) monolayer on gold have been investigated. Monolayer immobilization chemistry and surface coverage of reactive ssDNA probes were studied by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Orientation of the ssDNA probes was determined by near edge X-ray absorption fine structure (NEXAFS). Target DNA hybridization on the DNA-MEG probe surfaces was measured by surface plasmon resonance (SPR) to demonstrate the utility of these probe surfaces for detection of DNA targets from both purified target DNA samples and complex biological mixtures such as blood serum. Data from complementary techniques showed that immobilized ssDNA density is strongly dependent on the spotted bulk DNA concentration and buffer ionic strength. Variation of the immobilized ssDNA density had a profound influence on the DNA probe orientation at the surface and subsequent target hybridization efficiency. With increasing surface probe density, NEXAFS polarization dependence results (followed by monitoring the N 1s → π* transition) indicate that the immobilized ssDNA molecules reorient towards a more upright position on the MEG monolayer. SPR assays of DNA targets from buffer and serum showed that DNA hybridization efficiency increased with decreasing surface probe density. However, target detection in serum was better on the "high density" probe surface than on the "high efficiency" probe surface. The amount of target detected for both ssDNA surfaces were several orders of magnitude poorer in serum than in purified DNA samples due to non-specific serum protein adsorption onto the sensing surface.

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C1sexcitation studies of diamond (111). II. Unoccupied surface states

Cited by 133 publications

References 35 publications

The fascinating physics of carbon surfaces: first-principles study of hydrogen on C(0 0 1), C(1 1 1) and graphene

The fascinating physics of carbon surfaces: first-principles study of hydrogen on C(0 0 1), C(1 1 1) and graphene

The potential application of ultra-nanocrystalline diamond films for heavy ion irradiation detection

Structure and DNA Hybridization Properties of Mixed Nucleic Acid/Maleimide−Ethylene Glycol Monolayers

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