Continuous-time photoelectron spectroscopy for monitoring monochromatic soft x-ray photodissociation of CF3Cl adsorbed on Si(111)−7×7

Chou, Li Fang; Chuang, W.-M.; Tsai, Wen‐Ta; Wang, S.-K.; Wu, Yu-Han; Wen, C.-R.

doi:10.1063/1.2794430

Cited by 8 publications

(4 citation statements)

References 13 publications

(5 reference statements)

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“…By tuning the excitation wavelength, it is possible to select specific transitions and break specific bonds. Selective bond breaking is an area of continuous expansion when SR is used as excitation source [26,27]. In UHV conditions, the radicals formed at the surface remain stable for long periods of time due to the low collision frequency under those very low vacuum conditions [5].…”

Section: Resultsmentioning

confidence: 99%

Polymer Surface Functionalization Using Plasma, Ultraviolet and Synchrotron Radiation

Weibel

2010

Composite Interfaces

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Polyurethane (PU) and polystyrene (PS) films were functionalized by ultraviolet (UV) or selective synchrotron radiations (SR) in the presence of reactive gases. The UV-PU results were compared with lowpressure plasma treatments of the same films. Oxygen or acrylic acid vapours (AA) were used as reactive gases. X-ray photoelectron spectroscopy measurements of UV modified films in the presence of oxygen or AA matched the RF-plasma treatments results. It is shown that COO and C=O functional groups were incorporated at the polymer surface efficiently with both methodologies. In addition, near-edge X-ray absorption fine structure showed that a thin film of poly(acrylic acid) is formed over the PU and PS films during the UV irradiation in the presence of AA vapours. These results resemble previous AA low-power plasma treatments. PU and PS films were also selectively functionalized by SR using oxygen as reactive gas. Surface concentrations of COO and C=O functional groups were enhanced by C 1s → σ * C−C excitation after irradiation and oxygen introduction. This efficient surface functionalization was clearly observed in PS films which do not have CO and COO groups in their molecular structure. Excitations involving transitions to π * orbital (π * C=C , π * C=O ) led to much lower functionalization efficiency. The SR results can be explained by taking into account previous photon stimulated ion desorption studies of polymers. SR results may open new ways to functionalize polymer surfaces selectively and efficiently.

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Section: Resultsmentioning

confidence: 99%

Polymer Surface Functionalization Using Plasma, Ultraviolet and Synchrotron Radiation

Weibel

2010

Composite Interfaces

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“…The excellent properties of SR have encouraged researchers in the past to also look for selective bond dissociation in molecules and polymers. In particular, photon-stimulated ion desorption (PSID) studies combined with time-of-flight mass spectrometry (TOF-MS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy have been used to search for highly specific chemical bond scission using core-level photoexcitation. − The so-called “molecular knife or molecular scissor” effect was proposed where the localized energy in a particular core excitation would lead to selective molecular bond-breaking. , SR-selective photofragmentation was induced in the past using vacuum ultraviolet (VUV) , as well as inner shell excitations. − In several of those investigations, it was observed that some ions were selectively dissociated, but others were rapidly neutralized before fragmentation and desorption. , Recently, Nagaoka et al, in an experimental and computational study, have shown that for an effective molecular dissociation it is necessary to satisfy two conditions: the atomic sites to be distinguished should be connected through a chain of saturated bonds and located far from each other. In this way, the electron migration would be reduced.…”

Section: Introductionmentioning

confidence: 99%

Polarization Dependence in the Carbon K-Edge Photofragmentation of MAPDST Photoresist: An Experimental and Theoretical Study

et al. 2018

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The use of tunable soft X-rays from synchrotron radiation (SR) opens the possibility of inducing selective chemical bond scission because of its high localization in a chemical bond. The selective fragmentation of a potential extreme ultraviolet resist, poly(4-(methacryloyloxy) phenyldimethylsulfoniumtriflate) (MAPDST), was examined using inner shell-polarized SR excitation. Selective bond dissociation processes were studied using a combination of carbon K-edge excitation, angle-resolved irradiation, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Detailed theoretical calculations carried out with the FEFF9 modeling program allowed the interpretation of all the observed experimental features. NEXAFS results indicated that the aromatic group of the polymer lies parallel to the substrate surface. FEFF9 theoretical calculations confirmed the origin of the splitting of the main C 1s → πCC * resonances observed. The transition C 1s → παCC * (285.3 eV) can be associated with the four internal carbons of the aromatic ring. The transition C 1s → πβCC * (286.9 eV) was assigned to the carbon atoms attached to the oxygen and sulfur atoms. According to the theoretical calculations, the origin of the splitting is due to the different absolute energy of C 1s. The results showed a strong selective dissociation effect when the excitation energy was tuned to the C 1s → παCC * transition and the electric field vector of the photon was perpendicular to the substrate plane (grazing angle). On the contrary, other transitions were in general less affected. When the SR irradiation angle changed from grazing to normal incidence, the intensity of the C 1s → πCC * transitions was almost unaffected by 285.3 eV photons. The experimental results suggest that site-specific core excitation combined with the direction of the electric field vector of the incidence SR can efficiently control the localization of the photon energy to produce selective bond dissociation in MAPDST thin films. The results presented here can also be useful to guide new processing lithographic methods for extreme ultraviolet lithography using the polarization properties of light in ordered polymeric thin films.

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“…the ion yield was monitored continually under irradiation of probe light at a wavelength above the silicon threshold. This operational mode is important in terms of evaluation of the beam damage, due to photon electron spectroscopy …”

Section: Introductionmentioning

confidence: 99%

Adsorption of formic acid on Si(111)7 × 7 at room temperature: a valence band photoemission and Si2p photodesorption study

Carbone

2014

Surf. Interface Anal.

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Formic acid is the simplest of the carboxylic acids and a model adsorption system for several surfaces. In spite of the simple structure, formic acid reactivity and photoreactivity may be quite complex. In this paper, a study is presented on the deuterated formic acid adsorption on Si(111)7 × 7 at room temperature. The study is performed both by valence band photoemission and by photon‐stimulated desorption as a function of time and of photon energy in the 90–120 eV range. A primarily adsorption on rest atoms is found. This is verified by monitoring rest atoms and adatom intensity as a function of formic acid exposure. Further checks were made to control that surface adatoms were still free to react after the adsorption of formic acid. The photon stimulated desorption produces 5 single positively charged fragments: D+, O+, OD+ CO+ and CDO+. Possible fragmentation mechanisms are discussed. Copyright © 2014 John Wiley & Sons, Ltd.

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Continuous-time photoelectron spectroscopy for monitoring monochromatic soft x-ray photodissociation of CF3Cl adsorbed on Si(111)−7×7

Abstract: A single centre water splitting dye complex adsorbed on rutile TiO2(110): Photoemission, x-ray absorption, and optical spectroscopy

Cited by 8 publications

References 13 publications

Polymer Surface Functionalization Using Plasma, Ultraviolet and Synchrotron Radiation

Polymer Surface Functionalization Using Plasma, Ultraviolet and Synchrotron Radiation

Polarization Dependence in the Carbon K-Edge Photofragmentation of MAPDST Photoresist: An Experimental and Theoretical Study

Adsorption of formic acid on Si(111)7 × 7 at room temperature: a valence band photoemission and Si2p photodesorption study

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