Surface Processes in Laser-Induced Etching of Silicon Studied by X-Ray Photoelectron Spectroscopy

1986 ◽  
Vol 75 ◽  
Author(s):  
Masataka Hirose ◽  
Tsuyoshi Ogura
Keyword(s):  
Photoelectron Spectroscopy ◽  
Silicon Surface ◽  
Valence Electron ◽  
Surface Region ◽  
Reaction Products ◽  
X Ray ◽  
Photochemical Etching ◽  
Arf Excimer Laser ◽  
Laser Induced Etching

AbstractA silicon surface exposed to NF3 gas was irradiated with an ArF excimer laser beam. The reaction products on the surface and their chemical bonding features were studied by in-situ x-ray photoelectron spectroscopy at each step of the photochemical etching. It was found that SiFX (1≤X≤4) units and molecular fluorine exist in the reacting surface region. The surface Si-Si bonds attacked with fluorine are progressively fluorinated and the final surface products are mainly SiF4 and SiF3. A possible mechanism of fluorine etching is discussed on the basis of a valence electron transfer (VET) model.

scholarly journals An In Situ Temperature-Dependent Study of La2O3 Reactivation Process

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaohong Zhou ◽  
Evgeny I. Vovk ◽  
Yang Liu ◽  
Cairu Guan ◽  
Yong Yang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Region ◽  
Oxidative Coupling Of Methane ◽  
Ex Situ ◽  
Structure Evolution ◽  
Signal Loss ◽  
Air Exposure ◽  
X Ray ◽  
Air Contamination

Lanthanum-containing materials are widely used in oxidative catalytic and electrocatalytic reactions such as oxidative coupling of methane (OCM) and solid oxide fuel cells (SOFCs). However, many of these materials are highly susceptible to air contamination which means ex situ characterization results generally cannot be associated with their reactivity. In this study, the activation processes of an in situ–prepared bulk La2O2CO3 sample and an ex situ as-prepared La(OH)3 sample are in situ investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and online mass spectroscopy (MS). Results indicate that the La2O2CO3 sample, during linear heating to 800°C, always contains some carbonates near the surface region, which supports a two-step model of bulk carbonate decomposition through surface sites. The La(OH)3 sample structure evolution is more complex due to contaminations from air exposure. Together with TGA results, online mass analysis of water and CO2 signal loss showed that three major catalyst structure phase change steps and a preheating up to 800°C are required for the as-prepared material to be transferred to La2O3. This process is carefully investigated combining the three in situ methodologies. XPS and XRD data further reveal transformations of variety of in situ surface structures and forms including hybrid phases with hydroxyl, carbonates, and oxide as the sample heated to different temperatures within the range from 200 to 800°C. The results provide useful insights on the activation and deactivation of La-contained materials.

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

In situ Hard X-ray Photoelectron Spectroscopy on the Origin of Irreversibility in Electrochromic LixWO3 Thin Films

2021 ◽  
pp. 150898
Author(s):  
Makoto Takayanagi ◽  
Takashi Tsuchiya ◽  
Shigenori Ueda ◽  
Tohru Higuchi ◽  
Kazuya Terabe
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
X Ray

Incorporation and Role of Nitrogen During Oxynitridation of Silicon Studied by Photoelectron Spectroscopy

1999 ◽  
Vol 567 ◽  
Author(s):  
Masayuki Suzuki ◽  
Yoji Saito
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Oxide Films ◽  
Silicon Surfaces ◽  
Gaseous Mixtures ◽  
X Ray ◽  
Initial Stage ◽  
Thermal Stability Of

ABSTRACTWe tried direct oxynitridation of silicon surfaces by remote-plasma-exited nitrogen and oxygen gaseous mixtures at 700°C in a high vacuum. The oxynitrided surfaces were investigated with in-situ X-ray photoelectron spectroscopy. With increase of the oxynitridation time, the surface density of nitrogen gradually increases, but that of oxygen shows nearly saturation behavior after the rapid increase in the initial stage. We also annealed the grown oxynitride and oxide films to investigate the role of the contained nitrogen. The desorption rate of oxygen from the oxynitride films is much less than that from oxide films. We confirmed that nitrogen stabilizes the thermal stability of these oxynitride films.

Formation of a ZnO/ZnS interface passivation layer on (NH4)2S treated In0.53Ga0.47As: Electrical and in-situ X-ray photoelectron spectroscopy characterization

2016 ◽  
Vol 55 (8S2) ◽  
pp. 08PC02 ◽  
Author(s):  
Antonio T. Lucero ◽  
Young-Chul Byun ◽  
Xiaoye Qin ◽  
Lanxia Cheng ◽  
Hyoungsub Kim ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Passivation Layer ◽  
X Ray ◽  
Interface Passivation

scholarly journals In situ investigation of degradation at organometal halide perovskite surfaces by X-ray photoelectron spectroscopy at realistic water vapour pressure

2017 ◽  
Vol 53 (37) ◽  
pp. 5231-5234 ◽  
Author(s):  
Jack Chun-Ren Ke ◽  
Alex S. Walton ◽  
David J. Lewis ◽  
Aleksander Tedstone ◽  
Paul O'Brien ◽  
...  
Keyword(s):  
Water Vapour ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Water Vapour Pressure ◽  
Lead Iodide ◽  
X Ray ◽  
In Situ Investigation ◽  
Organometal Halide Perovskite ◽  
Methylammonium Lead Iodide

Near-ambient-pressure X-ray photoelectron spectroscopy enables the study of the reaction of in situ-prepared methylammonium lead iodide (MAPI) perovskite at realistic water vapour pressures for the first time.

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