scholarly journals Passive Films and Blistering of Titanium

1999 ◽  
Vol 556 ◽  
Author(s):  
Peter J. Bedrossian ◽  
Joseph C. Farmer ◽  
R. Daniel McCright ◽  
Douglas L. Phinney ◽  
John C. Estill
Keyword(s):  
Electrochemical Cell ◽  
Yucca Mountain ◽  
Passive Films ◽  
Photoemission Spectroscopy ◽  
X Ray ◽  
Force Microscopy ◽  
Hydride Formation ◽  
Atomic Force ◽  
One Year

AbstractCoupons of titanium alloys under consideration as components of the Engineered Barrier System in the proposed repository at Yucca Mountain have been evaluatedfor their passive film composition and stability. Oxide depths and compositions on specimens exposed in long-term corrosion testing for one year were determined with x-ray photoemission spectroscopy. The specimens removed from long-term testing, as well as separate coupons polarized cathodically in an electrochemical cell, exhibited blistering associated with hydride formation in both scanning electron microscopy and atomic force microscopy.

Low Temperature Si Direct Bonding by Plasma Activation

2000 ◽  
Vol 657 ◽  
Author(s):  
Yonah Cho ◽  
Nathan W. Cheung
Keyword(s):  
Surface Energy ◽  
Oxygen Plasma ◽  
Photoemission Spectroscopy ◽  
X Ray ◽  
Force Microscopy ◽  
Plasma Irradiation ◽  
Atomic Force ◽  
Plasma Activation ◽  
Physical Effects ◽  
Si Wafer

ABSTRACTChemical and physical effects of plasma exposed Si wafer pairs were investigated on Si wafer bonding. Oxygen plasma treated Si wafer pairs bonded more strongly at room temperature compared to chemically cleaned, hydrophilic and hydrophobic Si. After 50 hours of annealing at 105°C, the surface energy of the bonded Si pair reached the surface energy of bulk Si (100). X- ray photoemission spectroscopy (XPS) measurements indicated that the exposure of both hydrophilic and hydrophobic Si to oxygen plasma increased a SiO2 like state in the surface layer to a depth of 1.5 nm. Atomic force microscopy (AFM) study showed that plasma irradiation at 300 watts up to 30 seconds did not change surface roughness below 0.5 nm. Exposure to He plasma or N2 did result in enhanced bonding after annealing at 165°C, however, over smaller areas.

scholarly journals Graphene Langmuir-Schaefer films Decorated by Pd Nanoparticles for NO2 and H2 Gas Sensors

2019 ◽  
Vol 19 (2) ◽  
pp. 64-69 ◽  
Author(s):  
Dmytro Kostiuk ◽  
Stefan Luby ◽  
Peter Siffalovic ◽  
Monika Benkovicova ◽  
Jan Ivanco ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Pd Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Long Term Stability ◽  
Atomic Force ◽  
Few Layer Graphene

Abstract NO2 and H2 gas sensing by few-layer graphene (FLG) were studied in dependence on the annealing and decoration of graphene by palladium nanoparticles (NPs). Graphene was deposited onto SiO2 (500 nm)/Si substrates by a modified Langmuir-Schaefer technique. A solution of FLG flakes in 1-methyl-2-pyrrolidone was obtained by a mild sonication of the expanded milled graphite. FLG films were characterized by atomic force microscopy, X-ray diffraction, Raman spectroscopy, and the Brunnauer-Emmett-Teller method. Average FLG flake thickness and lateral dimension were 5 nm and 300 nm, respectively. Drop casting of Pd NP (6–7 nm) solution onto FLG film was applied to decorate graphene by Pd. The room temperature (RT) resistance of the samples was stabilized at 15 kΩ by vacuum annealing. Heating cycles of FLG film revealed its semiconducting character. The gas sensing was tested in the mixtures of dry air with H2 gas (10 to 10 000 ppm) and NO2 gas (2 to 200 ppm) between RT and 200 °C. The response of 26 % to H2 was achieved by FLG with Pd decoration at 70 °C and 10 000 ppm of H2 in the mixture. Pure FLG film did not show any response to H2. The response of FLG with Pd to 6 ppm of NO2 at RT was ≥ 23 %. It is 2 times larger than that of the pure FLG sample. Long term stability of sensors was studied.

Novel Protein Crystal Growth Electrochemical Cell For Applications In X-ray Diffraction and Atomic Force Microscopy

2011 ◽  
Vol 11 (9) ◽  
pp. 3917-3922 ◽  
Author(s):  
Gabriela Gil-Alvaradejo ◽  
Rayana R. Ruiz-Arellano ◽  
Christopher Owen ◽  
Adela Rodríguez-Romero ◽  
Enrique Rudiño-Piñera ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Crystal Growth ◽  
Electrochemical Cell ◽  
Protein Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Protein Crystal Growth ◽  
Novel Protein

Effect of GaN Surface Treatment on the Morphological and Optoelectronic Response of Violet Light Emitting Diodes

2004 ◽  
Vol 831 ◽  
Author(s):  
Muhammad Jamil ◽  
James R. Grandusky ◽  
Fatemeh Shahedipour-Sandvik
Keyword(s):  
Organic Solvents ◽  
Light Emitting Diode ◽  
Photoemission Spectroscopy ◽  
Light Emitting ◽  
X Ray ◽  
Force Microscopy ◽  
Treatment Processes ◽  
Atomic Force ◽  
Short Period ◽  
High Roughness

ABSTRACTWe report on the study of the effect of various surface chemical treatment processes of n-GaN template layers used for subsequent growth of light emitting diode (LED) structures. The treatment procedure included cleaning in organic solvents, organic solvents followed by 5 minutes of HCl, organic solvents and 5 minutes of HCl followed by 2 minutes and finally 10 minutes of HF treatment. Chemical, optical and electrical properties of the surfaces of GaN and InGaN-based LED structures were systematically investigated by x-ray photoemission spectroscopy (XPS), auger electron spectroscopy (AES), atomic force microscopy (AFM), photoluminescence (PL) and electroluminescence (EL) spectroscopy. GaN layers that were grown on the samples treated with HCl and HF showed dramatically different surfaces having high density of 3D structures with high roughness. As measured by AFM, growth of the LED structure on top of the GaN layer continued the 3D-growth mode. LED structures grown on the HCl and HF treated GaN template layers showed minimal to no PL and EL emission and failed after a short period. We suggest a qualitative model of the growth that could potentially explain the underlying phenomena leading to such pronounced changes in the optoelectronic properties and surface conditions of the LED structures due to the treatment of the initial template layers.

Atomic Structure of Non-Basal-Plane SiC Surfaces: Hydrogen Etching and Surface Phase Transformations

2006 ◽  
Vol 911 ◽  
Author(s):  
Serguei Soubatch ◽  
Wai Y. Lee ◽  
Martin Hetzel ◽  
Chariya Virojanadara ◽  
Camilla Coletti ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Hydrogen Etching ◽  
X Ray ◽  
Force Microscopy ◽  
Low Energy Electron Diffraction ◽  
Atomic Force ◽  
Surface Phases ◽  
Low Energy Electron

AbstractA-plane (11-20) and diagonal cut (1-102) and (-110-2) surfaces of 4H-SiC have been investigated using atomic force microscopy (AFM), low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). After hydrogen etching the surfaces show large, flat terraces. On SiC(11-20) steps down to single atomic heights are observed. On the diagonal cut surfaces steps run parallel and perpendicular to the [-1101] direction, yet drastically different morphologies for the two isomorphic orientations are found. All surfaces immediately display a sharp LEED pattern. For SiC(1-102) and SiC(-110-2) the additional significant presence of oxygen in the AES spectra indicates the development of an ordered oxide. All three surfaces show an oxygen free, well ordered surface after Si deposition and annealing. A transformation between different surface phases is observed upon annealing.

Scanning Photoemission Spectromicroscopic Study of 4-nm Ultrathin SiO3.4 Protrusions Probe-Induced on the Native SiO2 Layer

2011 ◽  
Vol 17 (6) ◽  
pp. 944-949 ◽  
Author(s):  
Rupesh S. Devan ◽  
Shun-Yu Gao ◽  
Yu-Rong Lin ◽  
Shun-Rong Cheng ◽  
Chia-Er Hsu ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Large Area ◽  
Xps Spectra ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Peak Intensity ◽  
Content Ratio ◽  
Si Content ◽  
Chemical Distribution

AbstractAtomic force microscopy probe-induced large-area ultrathin SiOx (x ≡ O/Si content ratio and x > 2) protrusions only a few nanometers high on a SiO2 layer were characterized by scanning photoemission microscopy (SPEM) and X-ray photoemission spectroscopy (XPS). SPEM images of the large-area ultrathin SiOx protrusions directly showed the surface chemical distribution and chemical state specifications. The peak intensity ratios of the XPS spectra of the large-area ultrathin SiOx protrusions provided the elemental quantification of the Si 2p core levels and Si oxidation states (such as the Si4+, Si3+, Si2+, and Si1+ species). The O/Si content ratio (x) was evidently determined by the height of the large-area ultrathin SiOx protrusions.

THE EFFECTS OF ANNEALING OF A p-TYPE PHOTOLUMINESCENT POROUS SILICON IN VACUUM

2002 ◽  
Vol 09 (01) ◽  
pp. 261-265
Author(s):  
H. J. SHIN ◽  
M. K LEE ◽  
C. C. HWANG ◽  
K. J. KIM ◽  
T.-H. KANG ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Annealing Temperature ◽  
Photoemission Spectroscopy ◽  
Photoluminescence Quenching ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chemical States ◽  
Average Size ◽  
P Type

The changes of the structure and chemical states of photoluminescent p-type porous silicon (PS) caused by annealing in vacuum were investigated with atomic force microscopy and X-ray photoemission spectroscopy. The relative intensities of the silicon dioxide and suboxide peaks increased with the annealing temperature. The average size of the fine crystallites of the as-prepared samples was 5–10 nm and became 50–100 nm after being annealed at 550°C. The cause of photoluminescence quenching upon annealing is discussed.

Analysis of the injection layer of PTCDA in OLEDs using x-ray photoemission spectroscopy and atomic force microscopy

2006 ◽  
Vol 15 (6) ◽  
pp. 1296-1300 ◽  
Author(s):  
Ou Gu-Ping ◽  
Song Zhen ◽  
Wu You-Yu ◽  
Chen Xiao-Qiang ◽  
Zhang Fu-Jia
Keyword(s):  
Atomic Force Microscopy ◽  
Photoemission Spectroscopy ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

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