scholarly journals Effect of nanocoating morphology on the signal of X-ray Photoelectron Spectroscopy

2021 ◽  
Vol 2144 (1) ◽  
pp. 012007
Author(s):  
V P Afanas’ev ◽  
L G Lobanova ◽  
D N Selyakov ◽  
M A Semenov-Shefov
Keyword(s):  
Photoelectron Spectroscopy ◽  
Strong Dependence ◽  
Cluster Structure ◽  
Substrate Material ◽  
Homogeneous Layer ◽  
Viewing Angle ◽  
X Ray ◽  
Plane Parallel ◽  
Straight Line ◽  
The Mathematical Model

Abstract The paper considers the application of the traditional X-ray photoelectron spectroscopy (XPS) methodology: the Overlayer Thickness Determination for the analysis of coating parameters. In particular situations considered in this work, it is energetically favorable for the atoms of the coating to form clusters, but not be evenly distributed on the surface of the substrate material. The change in the XPS signal is analyzed in situations when the coating is not a plane-parallel homogeneous layer, but an island (cluster) structure. The mathematical model of the XPS signal formation is considered for the case of the cluster covering in the form of parallelepipeds. Photoelectron path distributions (in the coating material) analysis indicated a strong dependence of the signal on the viewing angle. For the purpose of analysis, experimental spectra were obtained for several samples: gold depositions of various thicknesses on a silicon substrate. The spectra were measured for different viewing angles of photoelectrons and interpreted within the Straight Line Approximation (SLA). It is shown that proposed simplest model of an island coating allows to describe the effect of a decrease in the value of the effective average coating thickness, determined in plane-parallel geometry, with an increase in the viewing angle, observed in XPS experiments with angular resolution.

Interface Characterization of PbTe/BaSi/Si Heterostructures Grown Using MBE

1992 ◽  
Vol 281 ◽  
Author(s):  
F. Santiago ◽  
D. Woody ◽  
T. K. Chu ◽  
C. A. Huber
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Energy ◽  
Substrate Material ◽  
Interfacial Region ◽  
X Ray ◽  
Interface Characterization ◽  
Spectroscopy Studies ◽  
Molecular Layers ◽  
Similar Growth

ABSTRACTA new substrate material consisting of a buffer layer of a Ba-Si compound was developed by making use of the chemical reaction between BaF2 and Si. This substrate is very promising for the integration of IV-VI semiconductor materials with silicon. PbTe films of excellent quality, as determined by X-ray and Reflected High Energy Electron Diffraction spectra, have been deposited over (111)- and (100)-oriented silicon wafers of 3 inch diameter. These PbTe films are (100)-oriented irrespective of the Si orientation. X-ray photoelectron spectroscopy studies reveal very interesting chemistry at the interface between Ba-Si and Te. They suggest that BaTe may form between PbTe and Ba-Si at their interface. This interfacial region, which is of the order of only a few molecular layers, appears to be critical in the success of the deposition. Thermal cycling showed that the PbTe/BaSi/Si system is mechanically very stable. The possibility of a similar growth mechanism for the deposition of II-VI semiconductors such as CdTe is considered.

Surface Structure of Sulfur Coated GaAs

1989 ◽  
Vol 163 ◽  
Author(s):  
Yoshihisa Fujisaki ◽  
Shigeo Goto
Keyword(s):  
Electron Beam ◽  
Surface Structure ◽  
Chemical Bond ◽  
Photoelectron Spectroscopy ◽  
Strong Dependence ◽  
High Energy ◽  
Chemical Bonds ◽  
High Energy Electron ◽  
X Ray ◽  
Beam Diffraction

AbstractSurface structure of (NH4)2S treated GaAs. is investigated using PL (PhotoLuminescence), XPS (X-ray Photoelectron Spectroscopy) and RHEED (Reflection of High Energy Electron beam Diffraction). The data taken with these techniques show the strong dependence upon the crystal orientations coming from the stabilities of chemical bonds of Ga-S and As-S on GaAs crystals. The greater enhancement of PL intensity, the clearer RHEED patterns and the smaller amount of oxides on (111)A than (111)B implies the realization of a more stable structure composed mainly of the Ga-S chemical bond.

Effect of R.F. Power on Structures and Properties of Amorphous Fluorinated Carbon Films Prepared by PSII

2007 ◽  
Vol 353-358 ◽  
pp. 1829-1832
Author(s):  
Guang Ze Tang ◽  
Xin Xin Ma ◽  
Ming Ren Sun
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cluster Structure ◽  
Indentation Test ◽  
Plasma Source ◽  
Carbon Films ◽  
Power Structures ◽  
X Ray ◽  
Structures And Properties ◽  
Plasma Source Ion Implantation ◽  
Structure Density

Fluorinated amorphous carbon films (a-C:H:F) were deposited by plasma source ion implantation (PSII) with precursor gas of CH2FCF3 + C2H2 + H2 with various radio frequency (r.f.) power. Structures and properties evolution varied with r.f. power was discussed in detail. X-ray photoelectron spectroscopy (XPS), Raman spectrum, X-Ray reflection(XRR), atomic force microscopy (AFM) were used to analyze composition, chemical state, sp2 cluster structure, density and surface morphology of prepared films. Nano-indentation test was used to get hardness and modulus. The results show that with the increase of r.f. power, the size and amount of sp2 cluster increase, so does the surface roughness; however, the density and the hardness of films decrease.

Sputter Deposition and Thermally Induced Phase Transformation of Non-BCC Chromium Thin Films

1993 ◽  
Vol 311 ◽  
Author(s):  
M. J. O'Keefe ◽  
S. Horiuchi ◽  
J.J. Chu ◽  
J.J. Rigsbee
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Low Carbon Steel ◽  
Substrate Material ◽  
Low Carbon ◽  
Thermally Induced ◽  
X Ray ◽  
Sputter Deposited ◽  
Cr Film

ABSTRACTThe crystal structure of sputter deposited chromium thin films on Coming 7059 glass, polytetrafluoroethylene, and cold rolled (110) oriented low carbon steel α-Fe substrates was investigated as a function of O and C incorporation into the growing Cr film. The as-deposited crystal structure of the films was found by X-ray diffraction to be either highly oriented (110) BCC α-Cr or (200) oriented A-15 δ-Cr. Chemical analysis of the films by Auger electron spectroscopy determined that the δ-Cr phaseformed when the combined O and C impurity concentration in the film was ∼15-30 at.%. At total impurity concentrations above ∼30 at.% or below ∼10 at.% standard BCC α-Cr formed. The crystal structure of the films was not influenced by the substrate material. X-ray photoelectron spectroscopy of the Cr 2pl/2-2p3/2 orbitals indicated that the dominate binding state of both the BCC α-Cr and A-15 δ-Cr films was characteristic of elemental Cr. Vacuum annealing of the A-15 δ-Cr films at 500º for one hour transformed the crystal structure into BCC α-Cr without a measurable change in chemical composition. The incorporation of O and C into the growing Cr film is believed to impurity stabilize the A-15 structure and favor its formation over the BCC structure.

Optically Stimulated Electron Emission from Surface States of SiO2:Ge Films

2015 ◽  
Vol 644 ◽  
pp. 49-52
Author(s):  
Evgeny Buntov ◽  
Anatoly Zatsepin ◽  
Hans Joachim Fitting ◽  
Berndt Schmidt
Keyword(s):  
Electron Microscopy ◽  
Electron Emission ◽  
Photoelectron Spectroscopy ◽  
Strong Dependence ◽  
Surface States ◽  
Optical Devices ◽  
Energy Band Structure ◽  
X Ray ◽  
Parameter Values ◽  
Important Structure

Thin 30 nm SiO2films on silicon substrate implanted with Ge+ions and flash-annealed at 900°C are investigated by means of optically stimulated electron emission (OSEE). The materials under study may find a number of technological applications in optical devices and ultraviolet sensors. Samples attestation was performed by electron microscopy and x-ray photoelectron spectroscopy (XPS). XPS data revealed strong dependence between the germanium atoms state and annealing time. The application of Urbach rule and power Kane dependence allowed to fit OSEE spectra at different excitation energy ranges and to retrieve the important structure and energy parameters. Observed correlations between parameter values of Urbach-and Kane-related models suggest the implantation-induced changeover of both the vibronic subsystem and energy band structure.

scholarly journals Surface States of (100) O-Terminated Diamond: Towards Other 1 × 1:O Reconstruction Models

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1193
Author(s):  
Gonzalo Alba ◽  
M. Pilar Villar ◽  
Rodrigo Alcántara ◽  
Javier Navas ◽  
Daniel Araujo
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxidation Process ◽  
Strong Dependence ◽  
Surface States ◽  
Diamond Surface ◽  
Atomic Configuration ◽  
X Ray ◽  
Bioelectronic Device ◽  
Reconstruction Model

Diamond surface properties show a strong dependence on its chemical termination. Hydrogen-terminated and oxygen-terminated diamonds are the most studied terminations with many applications in the electronic and bioelectronic device field. One of the main techniques for the characterization of diamond surface terminations is X-ray photoelectron spectroscopy (XPS). In this sense, the use of angle-resolved XPS (ARXPS) experiments allows obtaining depth-dependent information used here to evidence (100)-O-terminated diamond surface atomic configuration when fabricated by acid treatment. The results were used to compare the chemistry changes occurring during the oxidation process using a sublayer XPS intensity model. The formation of non-diamond carbon phases at the subsurface and higher oxygen contents were shown to result from the oxygenation treatment. A new (100) 1 × 1:O surface reconstruction model is proposed to explain the XPS quantification results of O-terminated diamond.

scholarly journals Characterization of TiO2 films obtained by a wet chemical process

2017 ◽  
Vol 68 (7) ◽  
pp. 31-36 ◽  
Author(s):  
Asma Sedik ◽  
Ana M. Ferraria ◽  
Ana P. Carapeto ◽  
Bouzid Bellal ◽  
Mohamed Trari ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Strong Dependence ◽  
Sol Gel ◽  
Soda Lime ◽  
Alcoholic Solution ◽  
Soda Lime Glass ◽  
Experimental Conditions ◽  
Chemical Route ◽  
X Ray ◽  
Wet Chemical

AbstractTiO2has an easily tunable bandgap and a great absorption dye ability being widely used in many fields and in a number of fascinating applications. In this study, a wet chemical route, particularly a sol gel method using spin-coating is adopted to deposit TiO2thin films onto soda lime glass and silicon substrates. TiO2films were prepared by using an alcoholic solution of analytical reagent grade TiCl4as titanium precursor at various experimental conditions. The accent was put on the conditions of preparation (spin time, spin speed, precursor concentration, number of coating layersetc), doping and on the post-deposit treatment namely the drying and the crystallization. The results showed a strong dependence on the drying temperature and on the temperature and duration of the crystallization. We found that the solution preparation and its color are important for getting a reproducible final product. The Raman spectra recorded at room temperature, showed the characteristic peaks of anatase which appear at 143 and around 396 cm−1. These peaks confirm the presence of TiO2.The X-ray diffraction (XRD) was used to identify the crystalline characteristic of TiO2while the chemical states and relative amounts of the main elements existing in the samples were investigated by X-ray Photoelectron Spectroscopy (XPS). The morphology of the samples was visualized by AFM. We show by this work the feasibility to obtain different nanostructured TiO2by changing the concentration of the solution. Photocatalytic activity of TiO2films was evaluated. Rhodamine B is a recalcitrant dye and TiO2was successfully tested for its oxidation. An abatement of 60% was obtained under sunlight for an initial concentration of 10 mg/l.

scholarly journals Optimizing The Metalloid Content in Bulk Metallic Glasses

1999 ◽  
Vol 580 ◽  
Author(s):  
O. Jin ◽  
R. B. Schwarz ◽  
F. M. Alamgir ◽  
H. Jain
Keyword(s):  
Metallic Glasses ◽  
Photoelectron Spectroscopy ◽  
Short Range ◽  
Phosphorus Content ◽  
X Ray ◽  
P Concentration ◽  
Straight Line ◽  
P Content ◽  
Critical P Concentration ◽  
Straight Lines

AbstractWe have studied the effect of phosphorus content on the formation and properties of bulk Pd-Cu-P and Pd-Ni-P metallic glasses. It was found that the molar volumes of the Pd-Ni-P bulk glasses plotted as a function of P content follow a straight line whereas those for the Pd-Cu-P glasses follow two straight lines of different slopes, intersecting at a critical P concentration. The transition in molar volume behavior is attributed to a change in the alloy's short-range order with increasing P content. The origin of this structural change is discussed based on x-ray photoelectron spectroscopy (XPS) measurements.

Amorphous to anatase transformation in atomic layer deposited titania thin films induced by hydrothermal treatment at 120 °C

2008 ◽  
Vol 23 (9) ◽  
pp. 2472-2479 ◽  
Author(s):  
Zhaoming Zhang ◽  
Gerry Triani ◽  
Liang-Jen Fan
Keyword(s):  
Hydrothermal Treatment ◽  
Photoelectron Spectroscopy ◽  
Amorphous Film ◽  
Atomic Layer ◽  
Precursor Chemistry ◽  
Substrate Material ◽  
Edge Structure ◽  
X Ray ◽  
Titania Films ◽  
Polymeric Substrates

Hydrothermal treatment has been applied successfully to convert amorphous titania films to crystalline anatase at 120 °C, a temperature compatible with most polymeric substrates. The amorphous films were deposited at 80 °C using atomic layer deposition (ALD). The crystallinity of the films was monitored by x-ray absorption near edge structure (XANES), and the film composition was determined by x-ray photoelectron spectroscopy (XPS). The effect of precursor chemistry and substrate material was investigated. It was found that titania films produced from Ti isopropoxide are easier to crystallize than those from Ti tetrachloride as the Ti precursor. The amorphous to crystalline transformation can be achieved more readily with films deposited on Si than polycarbonate substrates. The effect of a “seed” layer on the amorphous to crystalline transformation was also studied. Preformed anatase crystallites between the Si substrate and the amorphous film were shown to accelerate the crystallization process. The possible mechanisms responsible for the phase transformation are discussed.

scholarly journals Preparation and Investigation of the Microtribological Properties of Graphene Oxide and Graphene Films via Electrostatic Layer-by-Layer Self-Assembly

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yongshou Hu ◽  
Haibing Ma ◽  
Wei Liu ◽  
Qianqian Lin ◽  
Bin Liu
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Adhesion Force ◽  
Strong Dependence ◽  
Layer By Layer ◽  
Crystal Silicon ◽  
X Ray ◽  
Graphene Films ◽  
Self Assembled

Graphene oxide (GO) films with controlled layers, deposited on single-crystal silicon substrates, were prepared by electrostatic self-assembly of negatively charged GO sheets. Afterward, graphene films were prepared by liquid-phase reduction of as-prepared GO films using hydrazine hydrate. The microstructures and microtribological properties of the samples were studied using X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, UV-visabsorption spectroscopy, water contact angle measurement, and atomic force microscopy. It is found that, whether GO films or graphene films, the adhesion force and the coefficients of friction both show strong dependence on the number of self-assembled layers, which both allow a downward trend as the number of self-assembled layers increases due to the interlayer sliding and the puckering effect when the tip slipped across the top surface of the films. Moreover, in comparison with the GO films with the same self-assembled layers, the graphene films possess lower adhesion force and coefficient of friction attributed to the difference of surface functional groups.

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