Influence of defects on surface scattering of UV photoemitted electrons in near perfect Si(111)1×1-H

Akremi, A.; Lacharme, J.-P.; Sébenne, C.A.

doi:10.1016/s0039-6028(97)01016-9

Cited by 12 publications

(14 citation statements)

References 11 publications

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“…-For the upper valence band, the narrowest edgewidth was 110 meV at room temperature [7] as measured by photoemission yield spectroscopy in the 4-6.7 eV photon energy range with an instrument resolution (12 me V) significantly less than k T It is consistent with the high-kinetic-energy tailing of the Si 2p core level.…”

Section: -Discussionsupporting

confidence: 61%

“…Only the dipole effect may be incriminated: it fits with the absence of band bending and the observed asymmetry. Moreover, a (strong) contamination by 4 percents of a monolayer of oxygen along the hydrogenated surface has been found to increase the edgewidth to 300 meV, the ionisation energy of the system being decreased by the same amount [7]. Possibly, an undetected oxygen contamination may always be high enough to maintain, as a OH dipole effect, the relatively wide and asymmetrical linewidth observed.…”

Section: -Discussionmentioning

confidence: 96%

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Photoemission thresholds and linewidths in semiconductors: The contributions of electrostatics

Sébenne¹

1998

Nouv Cim D

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It is often considered that the linewidth, for a core level, or the edgewidth, for a band, is governed by the lifetime of the hole left upon excitation of the photoemitted electron. In most cases, the line profiles are actually driven by hardly controlled surface parameters. In the present paper, the particular case of semiconductors is considered; the presence of fixed-point charges, both along the surface and in the bulk, is shown to significantly contribute to linewidths (and edgewidths) in the photoemission process. A numerical treatment is presented in the specific case of n-type silicon. The effect of surface dipoles on photoemission peak profiles is discussed. PACS 79.60.Bm -Clean metal, semiconductor, and insulator surfaces. PACS 73.30 -Surface double layers, Schottky barriers, and work functions. PACS 01.30.Ee -Monographs and collections.

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Section: -Discussionsupporting

confidence: 61%

Section: -Discussionmentioning

confidence: 96%

Photoemission thresholds and linewidths in semiconductors: The contributions of electrostatics

Sébenne¹

1998

Nouv Cim D

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“…must match the experimental surface when predicting surface dipoles using DFT. These findings also suggest that the effective band-edge energies of a surface can be engineered to have a specific [33] Photoelectron Spectroscopy [48,49], [86,87] wxaMPS [83] dfT & MBPT [71] −0.40 v (n-Si) −0.49 ev −0.35 ev…”

Section: Band-edge Control Of Siliconmentioning

confidence: 81%

“…The dipole shift determined using impedance spectroscopy in contact with octamethylferrocene-CH 3 CN-1.0 M LiClO4 is measured as −0.4 V and −0.25 V for n and p-Si(111), respectively [33]. The dipole shift determined using photoelectron spectroscopy in contact with vacuum is measured as −0.49 eV [48,49], [86,87]. These results are summarized in Table 1 below.…”

Section: Band-edge Control Of Siliconmentioning

confidence: 90%

Computational insights into charge transfer across functionalized semiconductor surfaces

Kearney

Rockett

Ertekin

2017

Science and Technology of Advanced Materials

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A 1.23 V electrochemical difference is required as a minimum to drive PEC water-splitting, which can only be provided by a single semiconductor with an excessively large band-gap. An alternative strategy is to use two small band-gap semiconductors placed electrically in series. One semiconductor operates as the photocathode to drive H 2 -evolution while the other operates as the photoanode to drive O 2 -evolution, as shown in Figure 1. In this case, the electrochemical potential difference required to split water is partially provided by each semiconductor. Photoelectrochemical water-splitting is a promising carbon-free fuel production method for producing H 2 and O 2 gas from liquid water. These cells are typically composed of at least one semiconductor photoelectrode which is prone to degradation and/or oxidation. Various surface modifications are known for stabilizing semiconductor photoelectrodes, yet stabilization techniques are often accompanied by a decrease in photoelectrode performance. However, the impact of surface modification on charge transport and its consequence on performance is still lacking, creating a roadblock for further improvements. In this review, we discuss how density functional theory and finite-element device simulations are reliable tools for providing insight into charge transport across modified photoelectrodes.

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“…This value may be compared to other Si surface terminations as ͓Si͑111͒ :H͔ = 4.17 eV, 44,45 ͓Si͑111͒ − ͑7 ϫ 7͔͒ = 4.16 eV, 36 and ͓Si͑100͒ − ͑2 ϫ 1͔͒ = 4.21 eV. 36 Estimating the electron affinity of bulk silicon as 4.05 eV, 46 the surface dipole ␦ caused by the methyl monolayer was calculated to be ϳ−0.4 eV.…”

Section: Resultsmentioning

confidence: 99%

Chemical and electronic characterization of methyl-terminated Si(111) surfaces by high-resolution synchrotron photoelectron spectroscopy

et al. 2005

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The chemical state, electronic properties, and geometric structure of methyl-terminated Si͑111͒ surfaces prepared using a two-step chlorination/alkylation process were investigated using high-resolution synchrotron photoelectron spectroscopy and low-energy electron diffraction methods. The electron diffraction data indicated that the methylated Si surfaces maintained a ͑1 ϫ 1͒ structure, where the dangling bonds of the silicon surface atoms were terminated by methyl groups. The surfaces were stable to annealing at 720 K. The high degree of ordering was reflected in a well-resolved vibrational fine structure of the carbon 1s photoelectron emission, with the fine structure arising from the excitation of C-H stretching vibrations having h = 0.38± 0.01 eV. The carbon-bonded surface Si atoms exhibited a well-defined x-ray photoelectron signal having a core level shift of 0.30± 0.01 eV relative to bulk Si. Electronically, the Si surface was close to the flat-band condition. The methyl termination produced a surface dipole of −0.4 eV. Surface states related to CH 3 and Si-C bonding orbitals were identified at binding energies of 7.7 and 5.4 eV, respectively. Nearly ideal passivation of Si͑111͒ surfaces can thus be achieved by methyl termination using the two-step chlorination/ alkylation process.

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Influence of defects on surface scattering of UV photoemitted electrons in near perfect Si(111)1×1-H

Cited by 12 publications

References 11 publications

Photoemission thresholds and linewidths in semiconductors: The contributions of electrostatics

Photoemission thresholds and linewidths in semiconductors: The contributions of electrostatics

Computational insights into charge transfer across functionalized semiconductor surfaces

Chemical and electronic characterization of methyl-terminated Si(111) surfaces by high-resolution synchrotron photoelectron spectroscopy

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