Atomic Contribution to Valence Band Density of States in Gallium Oxide and Silicon Oxide Nano Layered Films

2010 ◽  
Vol 297-301 ◽  
pp. 849-852
Author(s):  
Toshio Takeuchi ◽  
Jiro Nishinaga ◽  
Atsushi Kawaharazuka ◽  
Yoshiji Horikoshi
Keyword(s):  
Valence Band ◽  
Density Of States ◽  
Photoelectron Spectroscopy ◽  
Gallium Oxide ◽  
Silicon Oxide ◽  
Rf Magnetron Sputtering ◽  
X Ray ◽  
Analytical Technique ◽  
Sapphire Substrates ◽  
Atomic Contribution

High resolution X-ray photoelectron spectroscopy (XPS) is used to investigate the spectra of nanolayered films. Amorphous gallium oxide (Ga2O3)-silicon dioxide (SiO2) nanolayered thin films are grown using ultrahigh vacuum radio frequency (rf) magnetron sputtering on sapphire substrates at room temperature. Films are layered with 15-angstrom Ga2O3 oxide and 75-angstrom SiO2 for a total of 10 layers. Referring to atomic core levels, atomic contribution to valence band density of states is experimentally nominated. This analytical technique has particular applicability to the evaluation of the density of states with atomic contributions.

Valence band density of states and X-ray photoelectron spectrum of GaS

1978 ◽  
Vol 56 (6) ◽  
pp. 700-703 ◽  
Author(s):  
A. Balzarotti ◽  
R. Girlanda ◽  
V. Grasso ◽  
E. Doni ◽  
F. Antonangeli ◽  
...  
Keyword(s):  
Fine Structure ◽  
Valence Band ◽  
Density Of States ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectrum ◽  
Tight Binding ◽  
Single Layer ◽  
Two Dimensional ◽  
X Ray ◽  
Dimensional Approximation

The valence band density of states of GaS has been investigated by X-ray photoelectron spectroscopy and the spectrum has been interpreted on the basis of a single layer tight-binding calculation. Our two-dimensional approximation seems largely appropriate to reproduce the main experimental features of the valence band density of states of GaS, as previously found in the case of InSe. It can also explain to some extent the fine structure in the ultraviolet photoemission spectra recently measured with the synchroton radiation.

Valence Band Alignment of Ultra-Thin SiO2/Si Interfaces As Determined By High Resolution X-Ray Photoelectron Spectroscopy

1995 ◽  
Vol 386 ◽  
Author(s):  
J. L. Alay ◽  
M. Fukuda ◽  
C. H. Bjorkman ◽  
K. Nakagawa ◽  
S. Sasaki ◽  
...  
Keyword(s):  
High Resolution ◽  
Valence Band ◽  
Density Of States ◽  
Photoelectron Spectroscopy ◽  
Oxide Thickness ◽  
Core Level ◽  
Band Alignment ◽  
X Ray ◽  
Charging Effect

ABSTRACTUltra-thin SiO2/Si(111) interfaces have been studied by high resolution x-ray photoelectron spectroscopy. The deconvolution of the Si 2p core-level peak reveals the presence of the suboxide states Si3+ and Si1+ and the nearly complete absence of Si2+. The energy shifts found in the Si 2p and O is core-level peaks arising from charging effects arc carefully corrected. The valence band density of states for ultra-thin (1.8 - 3.7 nm thick) SiO2 is obtained by subtracting the bulk Si contribution from the measured spcctrum and by taking into account the charging effect of SiO2 and bulk Si. Thus obtained valence band alignment of ultra-thin SiO2/Si(111) interfaces is found to be 4.36 ± 0.10 eV regardless of oxide thickness.

scholarly journals Surface Analysis of Chamber Coating Materials Exposed to CF4/O2 Plasma

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 105
Author(s):  
Seung Hyun Park ◽  
Kyung Eon Kim ◽  
Sang Jeen Hong
Keyword(s):  
Photoelectron Spectroscopy ◽  
Yttrium Aluminum Garnet ◽  
Silicon Oxide ◽  
Ceramic Materials ◽  
High Plasma ◽  
Coating Materials ◽  
Continuous Increase ◽  
X Ray ◽  
Bonding Structure ◽  
Manufacturing Environments

Coating the inner surfaces of high-powered plasma processing equipment has become crucial for reducing maintenance costs, process drift, and contaminants. The conventionally preferred alumina (Al2O3) coating has been replaced with yttria (Y2O3) due to the long-standing endurance achieved by fluorine-based etching; however, the continuous increase in radio frequency (RF) power necessitates the use of alternative coating materials to reduce process shift in a series of high-powered semiconductor manufacturing environments. In this study, we investigated the fluorine-based etching resistance of atmospheric pressure-sprayed alumina, yttria, yttrium aluminum garnet (YAG), and yttrium oxyfluoride (YOF). The prepared ceramic-coated samples were directly exposed to silicon oxide etching, and the surfaces of the plasma-exposed samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. We found that an ideal coating material must demonstrate high plasma-induced structure distortion by the fluorine atom from the radical. For endurance to fluorine-based plasma exposure, the bonding structure with fluoride was shown to be more effective than oxide-based ceramics. Thus, fluoride-based ceramic materials can be promising candidates for chamber coating materials.

scholarly journals Probing LaMO3 Metal and Oxygen Partial Density of States Using X-ray Emission, Absorption, and Photoelectron Spectroscopy

2015 ◽  
Vol 119 (4) ◽  
pp. 2063-2072 ◽  
Author(s):  
Wesley T. Hong ◽  
Kelsey A. Stoerzinger ◽  
Brian Moritz ◽  
Thomas P. Devereaux ◽  
Wanli Yang ◽  
...  
Keyword(s):  
Density Of States ◽  
Photoelectron Spectroscopy ◽  
Partial Density ◽  
X Ray ◽  
Partial Density Of States

Properties of Sputter Deposited ZnO Films Co-doped with Lithium and Phosphorus

2013 ◽  
Vol 1494 ◽  
pp. 77-82
Author(s):  
T. N. Oder ◽  
A. Smith ◽  
M. Freeman ◽  
M. McMaster ◽  
B. Cai ◽  
...  
Keyword(s):  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Hall Effect Measurements ◽  
Sputter Deposited ◽  
P Type ◽  
Post Deposition ◽  
Co Doped

ABSTRACTThin films of ZnO co-doped with lithium and phosphorus were deposited on sapphire substrates by RF magnetron sputtering. The films were sequentially deposited from ultra pure ZnO and Li3PO4 solid targets. Post deposition annealing was carried using a rapid thermal processor in O2 and N2 at temperatures ranging from 500 °C to 1000 °C for 3 min. Analyses performed using low temperature photoluminescence spectroscopy measurements reveal luminescence peaks at 3.359, 3.306, 3.245 eV for the co-doped samples. The x-ray diffraction 2θ-scans for all the films showed a single peak at about 34.4° with full width at half maximum of about 0.17°. Hall Effect measurements revealed conductivities that change from p-type to n-type over time.

X-ray photoelectron spectroscopy measurement of n-ZnO/p-NiO heterostructure valence-band offset

2009 ◽  
Vol 94 (2) ◽  
pp. 022108 ◽  
Author(s):  
R. Deng ◽  
B. Yao ◽  
Y. F. Li ◽  
Y. M. Zhao ◽  
B. H. Li ◽  
...  
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Band Offset ◽  
Valence Band Offset ◽  
X Ray ◽  
Spectroscopy Measurement

High Quality GaAs Mis Diodes With Very Low Surface State Density

1990 ◽  
Vol 209 ◽  
Author(s):  
Yoshihisa Fujisaki ◽  
Sumiko Sakai ◽  
Saburo Ataka ◽  
Kenji Shibata
Keyword(s):  
Chemical Vapor Deposition ◽  
Density Of States ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
State Density ◽  
High Quality ◽  
Metal Insulator ◽  
X Ray ◽  
Mis Devices

ABSTRACTHigh quality GaAs/SiO2 MIS( Metal Insulator Semiconductor ) diodes were fabricated using (NH4)2S treatment and photo-assisted CVD( Chemical Vapor Deposition ). The density of states at the GaAs and SiO2 interface is the order of 1011 cm-2eV-1 throughout the forbidden energy range, which is smaller by the order of two than that of the MIS devices made by the conventional CVD process. The mechanism attributable to the interface improvement was investigated through XPS( X-ray Photoelectron Spectroscopy ) analyses.

Electronic structure modification in Fe substituted β-Ga2O3 from resonant photoemission and soft x-ray absotption spectroscopies

2021 ◽  
Author(s):  
Sahadeb Ghosh ◽  
Mangala Nand ◽  
Rajiv Kamparath ◽  
Mukul Gupta ◽  
Devdatta M Phase ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Rf Magnetron Sputtering ◽  
Binding Energies ◽  
Transfer System ◽  
Structure Modification ◽  
X Ray ◽  
Resonant Photoemission ◽  
A Charge ◽  
Fe Substitution

Abstract Oriented thin films of β-(Ga1-xFex)2O3 have been deposited by RF magnetron sputtering on c-Al2O3 and GaN substrates. The itinerant character of Fe 3d states forming the top of the valence band (VB) of Fe substituted of β-Ga2O3 thin films has been determined from resonant photoelectron spectroscopy (RPES). Further, admixture of itinerant and localized character of these Fe 3d sates is obtained for larger binding energies i.e deeper of VB. The bottom of the conduction band (CB) for β-(Ga1-xFex)2O3 is also found to be strongly hybridized states involving Fe 3d and O 2p states as compared to that of Ga 4s in pristine β-Ga2O3. This suggests that β-Ga2O3 transforms from band like system to a charge transfer system with Fe substitution. Furthermore, the bandgap red shits with Fe composition, which has been found to be primarily related to the shift of the CB edge.

scholarly journals Valence band offset of InN∕AlN heterojunctions measured by x-ray photoelectron spectroscopy

2007 ◽  
Vol 90 (13) ◽  
pp. 132105 ◽  
Author(s):  
P. D. C. King ◽  
T. D. Veal ◽  
P. H. Jefferson ◽  
C. F. McConville ◽  
T. Wang ◽  
...  
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Band Offset ◽  
Valence Band Offset ◽  
X Ray

SiO2 films as heat resistant layers for protection of expandable polystyrene foam from flame torch–induced heat

2017 ◽  
Vol 31 (5) ◽  
pp. 657-667 ◽  
Author(s):  
S Varnagiris ◽  
S Tuckute ◽  
M Lelis ◽  
D Milcius
Keyword(s):  
Heat Resistance ◽  
Photoelectron Spectroscopy ◽  
Silicon Oxide ◽  
Plasma Generator ◽  
Expanded Polystyrene ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Heat Resistant ◽  
Pulsed Dc ◽  
Gas Atmosphere

Currently, polymeric insulation materials are widely used for energy saving in buildings. Despite of all benefits, these materials are generally sensitive to heat and highly flammable. This work discusses possibility to improve heat resistance of expanded polystyrene (EPS) foam using thin silicon dioxide (SiO2) films deposited by magnetron sputtering technique. In order to increase surface energy and adherence of SiO2 thin films to substrate EPS was plasma pretreated before films’ depositions using pulsed DC plasma generator for 40 s in argon gas. SiO2 formation was done in reactive argon and oxygen gas atmosphere. Laboratory made equipment was used for flame torch–induced heat resistance experiments. Results showed that silicon oxide films remains stable during heat resistance experiments up to 5 s and fully protects polystyrene (PS) substrate. Films are relatively stable for 30 s and 60 s and partially protect PS from melting and ignition. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy analysis confirmed that SiO2 layer, which is distributed uniformly on the EPS surface, could work as a good heat resistant material.

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