In situ surface composition and structure of InGaN and GaN thin films by time-of-flight mass spectroscopy of recoiled ions

1999 ◽  
Vol 17 (3) ◽  
pp. 1209 ◽  
Author(s):  
E. Kim ◽  
I. Berishev ◽  
A. Bensaoula ◽  
J. A. Schultz
Keyword(s):  
Thin Films ◽  
Mass Spectroscopy ◽  
Surface Composition ◽  
Time Of Flight ◽  
Composition And Structure

scholarly journals Time of Flight Mass Spectroscopy of Recoiled Ions Studies of Gallium Nitride Thin Film Deposition by Various Molecular Beam Epitaxial Methods

1998 ◽  
Vol 3 ◽  
Author(s):  
E. Kim ◽  
I. Berichev ◽  
A. Bensaoula ◽  
A. Schultz ◽  
K. Waters ◽  
...  
Keyword(s):  
Thin Films ◽  
Gallium Nitride ◽  
Mass Spectroscopy ◽  
Molecular Beam ◽  
Surface Composition ◽  
Time Of Flight ◽  
Thin Film Deposition ◽  
High Energy ◽  
Film Deposition ◽  
Ex Situ

Gallium Nitride (GaN) thin films were successfully grown by electron cyclotron resonance molecular beam epitaxy (ECR-MBE), gas source MBE (GSMBE), and chemical beam epitaxy (CBE). Time of flight mass spectroscopy of recoiled ions (TOF-MSRI) and reflection high energy electron diffraction (RHEED) were used in-situ to determine the surface composition, crystalline structure, and growth mode of GaN thin films deposited by the three MBE methods. The substrate nitridation and the buffer layers were monitored and optimized by TOF-MSRI and RHEED. For GSMBE, the gallium to nitrogen ratio is found to correlate well with ex-situ optical properties. In the case of CBE, carbon incorporation determines the surface morphology, crystalline quality and optical activity of the epilayers.

Surface composition and structure of nickel ultra-thin films deposited on Pd(111)

2007 ◽  
Vol 156-158 ◽  
pp. 405-408 ◽  
Author(s):  
M.F. Carazzolle ◽  
S.S. Maluf ◽  
A. de Siervo ◽  
P.A.P. Nascente ◽  
R. Landers ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Composition ◽  
Composition And Structure

scholarly journals Effect of Surface Composition and Structure of the Mesoporous Ni/KIT-6 Catalyst on Catalytic Hydrodeoxygenation Performance

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 889 ◽  
Author(s):  
Xianming Zhang ◽  
Shuang Chen ◽  
Fengjiao Wang ◽  
Lidan Deng ◽  
Jianmin Ren ◽  
...  
Keyword(s):  
Surface Composition ◽  
Reduction Temperature ◽  
Active Components ◽  
Composition And Structure ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Apparent Activation Energies ◽  
Loading Amount ◽  
Methane Selectivity

A series of Ni/KIT6 catalyst precursors with 25 wt.% Ni loading amount were reduced in H2 at 400, 450, 500, and 550 °C, respectively. The studied catalysts were investigated by XRD, Quasi in-situ XPS, BET, TEM, and H2-TPD/Ranalysis methods. It was found that reduction temperature is an important factor affecting the hydrodeoxygenation (HDO) performance of the studied catalysts because of the Strong Metal Support Interaction Effect (SMSI). The reduction temperature influences mainly the content of active components, crystal size, and the abilityfor adsorbing and activating H2. The developed pore structure and large specific surface area of the KIT-6 support favored the Ni dispersion. The RT450 catalyst, which was prepared in H2 atmosphere at 450 °C, has the best HDO performance. Ethyl acetate can be completely transformed and maintain 96.8% ethane selectivity and 3.2% methane selectivity at 300 °C. The calculated apparent activation energies of the prepared catalysts increased in the following order: RT550 > RT400 > RT500 > RT450.

Role of Ions in Bias Enhanced Nucleation of Diamond

1995 ◽  
Vol 388 ◽  
Author(s):  
J.M. Lannon ◽  
J.S. Gold ◽  
Cd. Stinespring
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Surface Composition ◽  
Hydrogen Ions ◽  
Ion Energy ◽  
Transfer Processes ◽  
Ion Interactions ◽  
Ion Energies

AbstractIon-surface interactions are thought to play a role in bias enhanced nucleation of diamond. To explore this hypothesis and understand the mechanisms, surface studies of hydrogen and hydrocarbon ion interactions with silicon and silicon carbide have been performed. the experiments were carried out at room temperature and used in-situ auger analyses to monitor the surface composition of thin films produced or modified by the ions. Ion energies ranged from 10 to 2000 eV. Hydrogen ions were found to modify silicon carbide thin films by removing silicon and converting the resulting carbon-rich layers to a mixture of sp2- and sp3-C. the interaction of hydrocarbon ions with silicon was shown to produce a thin film containing SiC-, sp2-, and sp3-C species. IN general, the relative amount of each species formed was dependent upon ion energy, fluence, and mass. the results of these studies, interpreted in terms of chemical and energy transfer processes, provide key insights into the mechanisms of bias enhanced nucleation.

scholarly journals In Situ, Real-Time Studies of Film Growth Processes Using Ion Scattering and Direct Recoil Spectroscopy Techniques

1999 ◽  
Vol 569 ◽  
Author(s):  
V.S. Smentkowskiv ◽  
A. R. Krauss ◽  
O. Auciello ◽  
J. Im ◽  
D.M. Gruen ◽  
...  
Keyword(s):  
Real Time ◽  
Mass Spectroscopy ◽  
Film Growth ◽  
Ion Beam ◽  
Time Of Flight ◽  
Analytical Techniques ◽  
Surface Species ◽  
Ion Scattering ◽  
Growth Processes

ABSTRACTTime-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) enables the characterization of the composition and structure of surfaces with 1–2 monolayer specificity. It will be shown that surface analysis is possible at ambient pressures greater than 3 mTorr using TOF-ISARS techniques; allowing for real-time, in situ studies of film growth processes. TOF-ISARS comprises three analytical techniques: ion scattering spectroscopy (ISS), which detects the backscattered primary ion beam; direct recoil spectroscopy (DRS), which detects the surface species recoiled into the forward scattering direction; and mass spectroscopy of recoiled ions (MSRI), which is a variant of DRS capable of isotopic resolution for all surface species - including H and He. The advantages and limitations of each of these techniques will be discussed.The use of the three TOF-ISARS methods for real-time, in situ film growth studies at high ambient pressures will be illustrated. It will be shown that MSRI analysis is possible during sputter deposition. It will be also be demonstrated that the analyzer used for MSRI can also be used for time of flight secondary ion mass spectroscopy (TOF-SIMS) under high vacuum conditions. The use of a single analyzer to perform the complimentary surface analytical techniques of MSRI and SIMS is unique. The dual functionality of the MSRI analyzer provides surface information not obtained when either MSRI or SIMS is used independently.

Surface composition and structure of palladium ultra-thin films deposited on Ni(111)

2006 ◽  
Vol 600 (11) ◽  
pp. 2268-2274 ◽  
Author(s):  
M.F. Carazzolle ◽  
S.S. Maluf ◽  
A. de Siervo ◽  
P.A.P. Nascente ◽  
R. Landers ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Composition ◽  
Composition And Structure

Ion Beam Induced Phase Transitions in Nickel and Cobalt thin Films on Silicon

1982 ◽  
Vol 40 ◽  
pp. 730-731
Author(s):  
L.J. Chen ◽  
T.T. Chang ◽  
C.Y. Hou ◽  
J.W. Mayer
Keyword(s):  
Thin Films ◽  
Phase Transitions ◽  
Surface Composition ◽  
Ion Beam ◽  
Metal Thin Films ◽  
Vlsi Technology ◽  
Composition And Structure ◽  
Potential Applications ◽  
Cobalt Thin Films ◽  
Atomic Mixing

Ion implantation metallurgy has received increasing attention because of its important applications in the modification of surface composition and structure of materials. Relatively low dose ion beam material modification can be achieved by ion-beam induced atomic mixing between thin film and its substrate. Ion beam mixing of metal thin films on silicon is by far the most widely studied system for its potential applications in VLSI technology. In this paper, we report the results of ion beam induced phase transitions in nickel and cobalt thin films on silicon.

Doubly curved crystal (DCC) X-ray optics and applications

2002 ◽  
Vol 17 (2) ◽  
pp. 99-103 ◽  
Author(s):  
Zewu Chen ◽  
Walter M. Gibson
Keyword(s):  
Thin Films ◽  
Low Power ◽  
X Rays ◽  
Enabling Technology ◽  
Ray Optics ◽  
X Ray ◽  
Composition And Structure ◽  
Composition Structure ◽  
Doubly Curved

Doubly curved crystal (DCC) X-ray optics provide an enabling technology for new portable, remote, and in situ applications of monochromatic X-rays for composition and structure analysis of amorphous, polycrystalline, and crystalline solids. Femtogram sensitivity for surface contamination, parts-per-billion (ppb) impurity levels for solids, and composition, structure and uniformity of thin films with compact, low power (20–50 W) source optic combinations are possible.

BaTiO3 Thin Films Prepared by Organometallic Chemical Vapor Deposition

1991 ◽  
Vol 243 ◽  
Author(s):  
L.A. Wills ◽  
B.W. Wessels ◽  
D.L. Schulz ◽  
T.J. Marks
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Composition And Structure ◽  
Volatile Precursors ◽  
Surface Morphologies ◽  
Organometallic Chemical Vapor Deposition

AbstractBaTiO3 thin films have been prepared by low pressure organometallic chemical vapor deposition on (100) MgO and (100) LaAlO3 substrates using the volatile precursors, titanium(IV) tetraisopropoxide and barium (hexafluoroacetylacetonate)2 (tetraglyme). The phase composition and structure of the films depends on the reactant partial pressure, growth temperature, and substrate. High quality, epitaxial BaTiO3 films can be prepared in-situ on LaAlO3 as confirmed by x-ray diffraction measurements. These BaTiO3 films exhibit smooth surface morphologies as evidenced by scanning electron microscopy. Electrical resistivity measurements indicate that the films are semi-insulating.

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