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Applied Surface Science (v.252, #6)
Distinguishing the effect of crystal-field screening from the effect of valence recharging on the 2p3/2 and 3d5/2 level energies of nanostructured copper by Chang Q. Sun /; L.K. Pan; T.P. Chen; X.W. Sun; S. Li; C.M. Li (pp. 2101-2107).
Incorporating the recent bond order–length–strength correlation mechanism [C.Q. Sun, Phys. Rev. B 69 (2004) 045105] to the size dependence of Auger photoelectron coincidence spectra of Cu nanoparticles with and without being passivated has enabled us to gain quantitative information about the 2p and 3d level energies of an isolated Cu atom and their shift upon bulk formation. The developed approach also enabled us to discriminate the effect of crystal-field screening from the effect of valence recharging (due to surface passivation and substrate–particle interaction) on the binding energies to the electrons at different energy levels of a specimen.
Keywords: Nanostructures; Crystal binding; Copper; Chemical reaction; Core level energy; Surface bond contraction
Benzene and NO on a Ru(001) surface: Electronic structure and bonding by Paula V. Jasen; Estela A. Gonzalez; Alfredo Juan; Graciela Brizuela (pp. 2108-2114).
We have theoretically studied the co-adsorption of benzene and NO on a Ru surface. The calculations were performed using the atom superposition and electron delocalisation-tight-binding (ASED-TB) method. We have modelled the Ru(001)–p(3×3)–4C6D6+2NO co-adsorbed layer from experimental data.We have confirmed that the more stable sites are hcp on the Ru for both benzene and NO co-adsorbates.The NO states are more stabilized in the co-adsorbed system. There is more bonding between RuN than RuC. We have described an important interaction of on H (from benzene) and the O (from a close NO). That results explain previous experimental reports and confirm suggested direct interaction.
Keywords: Benzene; Nitric oxide; Ruthenium; Theoretical calculation; Electronic structure
One-dimensional polyaniline nanostructures synthesized by interfacial polymerization in a solids-stabilized emulsion by Yongjun He (pp. 2115-2118).
One-dimensional polyaniline nanostructures were synthesized by interfacial polymerization in a solids-stabilized oil/water emulsion for the first time. The products were characterized with TEM, FTIR and UV–vis. FTIR analyses proved the polyaniline synthesized were of emeraldine salt form; the results of TEM showed that when MgCO3 and CaCO3 particles were used as emulsifiers, polyaniline nanofibers with an average diameter of 33nm and nanotubes with an average outer diameter of 28nm were obtained, respectively. Comparing to ordinary interfacial polymerization approach, our new route needed much less amount of oil phase and shorter polymerization time. A possible mechanism for the formation of one-dimensional polyaniline nanostructures was suggested.
Keywords: PACS; 81.05YsPolyaniline; Nanofibers; Nanotubes; Interfacial polymerization; Solids-stabilized emulsion
Self-ordered monolayers of fullerene derivatives assembled via bimolecular building block by Yunshen Zhou; B. Wang; Shengqiang Xiao; Y.L. Li; J.G. Hou (pp. 2119-2125).
We reported the design and fabrication of a C60 derivative with a uracil-like unit (U-C60), to form a bi-molecular building block with a C60 derivative with a 2,6-bis (acylamino) pyridine unit (DAP-C60) by complementary trident hydrogen-bonding array. By pre-organizing these two fullerene derivatives in solution, bimolecular blocks were formed via robust and highly directional trident hydrogen-bonding recognition between DAP-C60 and U-C60. Then, the bimolecular blocks were deposited on highly ordered pyrolytic graphite (HOPG). The structure of the monolayer was characterized using a scanning tunneling microscope. Well-ordered monolayer composed of the two fullerene derivatives of DAP-C60 and U-C60 was observed and the structure of the monolayer was modeled.
Keywords: PACS; 68.37.Ef; 68.43.HnHydrogen bond; Fullerene derivatives; Self-ordered monolayers; Scanning tunneling microscopy (STM)
Overcoat dependence of laser-induced damage threshold of 355nm HR coatings by Meiqiong Zhan; Hongbo He; Yuanan Zhao; Guanglei Tian; Jianda Shao; Zhengxiu Fan (pp. 2126-2130).
A series of HR coatings, with and without overcoat, were prepared by electron beam evaporation using the same deposition process. The laser-induced damage threshold (LIDT) was measured by a 355nm Nd:YAG laser with a pulse width of 8ns. Damage morphologies of samples were observed by Leica-DMRXE Microscope. The stress was measured by viewing the substrate deformation before and after coatings deposition using an optical interferometer. Reflectance of the samples was measured by Lambda 900 Spectrometer. The theoretical results of electric field distributions of the samples were calculate by thin film design software (TFCalc). It was found that SiO2 overcoat had improved the LIDT greatly, while MgF2 overcoat had little effect on the LIDT because of its high stress in the HR coatings. The damage morphologies were different among HR coatings with and without overcoats.
Keywords: PACS; 42.79.Wc; 61.80.BOvercoat; Laser-induced damage threshold; Electric field
Laser fluence, repetition rate and pulse duration effects on paint ablation by François Brygo; Ch. Dutouquet; F. Le Guern; R. Oltra; A. Semerok; J.M. Weulersse (pp. 2131-2138).
The efficiency (mm3/(Jpulse)) of laser ablation of paint was investigated with nanosecond pulsed Nd:YAG lasers ( λ=532nm) as a function of the following laser beam parameters: pulse repetition rate (1–10,000Hz), laser fluence (0.1–5J/cm2) and pulse duration (5ns and 100ns). In our study, the best ablation efficiency ( η≅0.3mm3/J) was obtained with the highest repetition rate (10kHz) at the fluence F=1.5J/cm2. This ablation efficiency can be associated with heat accumulation at high repetition rate, which leads to the ablation threshold decrease. Despite the low thermal diffusivity and the low optical absorption of the paint (thermal confinement regime), the ablation threshold fluence was found to depend on the pulse duration. At high laser fluence, the ablation efficiency was lower for 5ns pulse duration than for the one of 100ns. This difference in efficiency is probably due to a high absorption of the laser beam by the ejected matter or the plasma at high laser intensity. Accumulation of particles at high repetition rate laser ablation and surface shielding was studied by high speed imaging.
Keywords: PACS; 81.65 Cf; 42.62 Cf; 61.82 MsLaser ablation; Repetition rate; Paint stripping; Pulse duration; Thermal confinement regime
Surface analysis of inhibitor films formed by imidazolines and amides on mild steel in an acidic environment by O. Olivares-Xometl; N.V. Likhanova; M.A. Domínguez-Aguilar; J.M. Hallen; L.S. Zamudio; E. Arce (pp. 2139-2152).
Imidazolines and amidic precursors were synthesized with good yields through an optimized process. These compounds were evaluated as corrosion inhibitors in an aqueous solution of 1.0M HCl by gravimetric and polarization techniques. AISI 1018 carbon steel displayed a corrosion rate dependent on the molecular structure and concentration of inhibitor in the testing environment. Adsorption of inhibitors was found to follow the Langmuir's isotherm, this concept together with Gibbs’ free energy provided the basis to arrange corrosion inhibitors according to efficiency and stability. The surface analysis by AFM displayed that the damage on the metallic surface was considerably reduced in the presence of certain inhibitors. XPS determined the presence of a layer of inhibitor on the metal surface with protective properties.
Keywords: Carbon steel; Corrosion inhibitor (CI); Polarization scan; Acidic medium; Atomic force microscopy (AFM); X-ray photoelectron spectroscopy (XPS)
Preparation and characterization of GaN films by radio frequency magnetron sputtering and carbonized-reaction technique by C.G. Zhang; W.D. Chen; L.F. Bian; S.F. Song; C.C. Hsu (pp. 2153-2158).
Radio frequency magnetron sputtering/post-carbonized-reaction technique was adopted to prepare good-quality GaN films on Al2O3(0001) substrates. The sputtered Ga2O3 film doped with carbon was used as the precursor for GaN growth. X-ray diffraction (XRD) pattern reveals that the film consists of hexagonal wurtzite GaN. X-ray photoelectron spectroscopy (XPS) shows that no oxygen can be detected. Electrical and room-temperature photoluminescence measurements show that good-quality polycrystalline GaN films were successfully grown on Al2O3(0001) substrates.
Keywords: PACS; 78.55.Cr; 71,55.Eq; 74.25.GzGallium nitride films; Gallium Oxide; Carbonized-reaction
Effect of composition on the conductivity of CTAB–butanol–octane–nitrate salts (Al(NO3)3+Zn(NO3)2) microemulsions and on the surface and textural properties of resulting spinels ZnAl2O4 by A.E. Giannakas; A.K. Ladavos; G.S. Armatas; D.E. Petrakis; P.J. Pomonis (pp. 2159-2170).
The conductivity σ of a microemulsion series consisting of CTAB+butanol+octane, in which a solution of Al(NO3)3 0.8M+Zn(NO3)2 0.4M was gradually added, was studied at room temperature as a function of its composition φ. The addition of nitrate salts solution took place in four different ratios of (butanol+CTAB):octane=0.2, 0.4, 0.6 and 0.8. Initially, all those four systems are (water in oil, w/o) microemulsions and the gradual addition of the solution of the nitrate salts transforms them to bicontinuous ones. The conductivity increases gradually, but with different rate in each case, and the corresponding critical exponents at the percolation threshold were determined from the curves σ= f( φ). Next at three different compositions of microemulsions, corresponding to ratios (butanol+CTAB):octane=0.4, 0.6 and 0.8 and ratio of the nitrate salts solution x≈0.25, spinels ZnAl2O4 were isolated/prepared. XRD, SEM and N2 adsorption–desorption measurements were used to determine the structure and texture of those solids. From those measurements the surface area ( Sp), the pore volume ( Vp), the size of crystallites and the average pore connectivity ( c) were found. Those properties showed considerable variation and dependence on the composition of the original microemulsions employed in the preparation, a fact indicating that the structure and texture of the obtained solids can be manipulated at will via the composition of microemulsion used.
Keywords: Microemulsion; Conductivity; Spinels ZnAl; 2; O; 4
Investigation of orientation and packing of H8Si8O12 arrays on graphite by scanning tunneling microscopy by Dong-Lin Shieh; Feng-Chun Chen; Jong-Liang Lin (pp. 2171-2177).
The layer structures of H8Si8O12 molecules on highly oriented pyrolitic graphite have been investigated by scanning tunneling microscopy. Two kinds of ordered assemblies of H8Si8O12 monolayers are observed, with a unit cell of 6.5Å×6.5Å and 7.2Å×9.4Å, respectively. On the basis of the shapes and sizes of the H8Si8O12 STM images and the heights of the H8Si8O12 monolayers, H8Si8O12 can be adsorbed with one face of its cage structure in contact with the substrate surface or with a tilted orientation.
Keywords: Hydridosilsesquioxane; H; 8; Si; 8; O; 12; Scanning tunneling microscopy; Graphite
Corrosion inhibition of steel in sulphuric acid by pyrrolidine derivatives by M. Bouklah; A. Ouassini; B. Hammouti; A. El Idrissi (pp. 2178-2185).
Novel corrosion inhibitors, namely 1-{2-[(2-hydroxyethyl)thio]ethyl}pyrrolidin-2-one (P5) and {[2-(2-oxopyrrolidin-1-yl)ethyl]thio}acetic acid (P4), were synthesised and tested as corrosion inhibitors for steel in 0.5M H2SO4. The effects of P4 and P5 are also compared to their initial reactants 1-vinylpyrrolidin-2-one (P1), 2-mercaptoethanol (P2) and mercaptoacetic acid (P3). The study was carried out by weight loss measurements, potentiodynamic polarisation, linear polarisation resistance ( Rp) and electrochemical impedance spectroscopy (EIS) methods. The inhibition efficiency increases with the concentration of P5 to attain 89% at 5×10−3M. We note good agreement between the various methods explored. Polarisation measurements show also that the pyrrolidones act essentially as cathodic inhibitors. The cathodic curves indicate that the reduction of proton at the steel surface is an activating mechanism. P4 and P5 adsorb on the steel surface according to Langmuir adsorption model. Effect of temperature is also studied in the 298–353K range. Efficiency is explained by the theoretical studies.
Keywords: Pyrrolidone; Inhibition; Corrosion; Steel; Acid; Langmuir; Theoretical calculation
Recrystallization behavior of high-fluence N+-implanted GaAs studied by Raman spectroscopy by Jiqing Wang; Huibing Mao; Ziqiang Zhu; Qiang Zhao; Zhifeng Li; Wei Lu (pp. 2186-2190).
Raman spectroscopy was used to study the evolution of host lattice recrystallization in high-fluence N+-implanted GaAs. A high-fluence of N+ ions (>1015cm−2) was introduced into semi-insulating GaAs by the combinatorial implantation method. Subsequent thermal annealing at 800°C was carried out to re-grow the implantation-induced amorphous layers. The dependence of Raman parameters on N contents was systematically observed for each recrystallized cell. The volume of the newly formed crystallites with original orientation decreases with increasing fluences, whereas that of crystallites of other orientations increases after high-fluence implantation and annealing. The correlation length L, representing the size of crystalline regions with preserved translational symmetry, was determined by fitting the LO phonon signal with spatial correlation model. For 1016cm−2 implantation, the recrystallized layer consists of nano-meter-sized crystallites (∼30nm). The dimension of the recrystallized crystallites decreases with increasing N+ fluences, in good agreement with the model.
Keywords: PACS; 78.20.−e; 78.55.Cr; 61.72.VvGaNAs; Raman spectroscopy; Ion implantation
Electrocatalytic activity of ordered intermetallic PtSb for methanol electro-oxidation by Lijuan Zhang; Dingguo Xia (pp. 2191-2195).
Ordered intermetallic PtSb had been synthesized by arc-melted and then sintering treatment. The electro-oxidation of liquid methanol on PtSb was investigated at room temperature by cyclic voltammetry and chronoamperometry. The results are compared to those at a polycrystalline platinum electrode surface. It was found that PtSb intermetallic was catalytically more active than pure platinum according to the onset potential and current density. X-ray diffraction (XRD) and XPS technologies had been used to investigate the crystal structure and electron effect.
Keywords: PtSb intermetallic; Methanol electro-oxidation; X-ray diffraction; X-ray photoelectron spectroscopy; Fuel cells
Influence of titanium ions implantation on corrosion behavior of zirconium in 1M H2SO4 by D.Q. Peng; X.D. Bai; F. Pan; H. Sun; B.S. Chen (pp. 2196-2203).
In order to study the effect of titanium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted with titanium ions with fluence ranging from 1×1016 to 1×1017ions/cm2, using a metal vapor vacuum arc (MEVVA) source at an extraction voltage of 40kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zirconium in a 1M H2SO4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zirconium implanted with titanium ions. The larger the fluence, the better is the corrosion resistance of implanted sample. Finally, the mechanism of the corrosion behavior of titanium-implanted zirconium was discussed.
Keywords: Zirconium; Corrosion resistance; Titanium ion implantation; X-ray photoemission spectroscopy (XPS); Auger electron spectroscopy (AES)
White organic electroluminescent device with photovoltaic performances by Hanzhi Wei; Wenlian Li; Mingtao Li; Wenming Su; Qi. Xin; Jinghua Niu; Zhiqiang Zhang; Zhizhi Hu (pp. 2204-2208).
Organic device with structure of indium tin oxide (ITO)/1,3,5-tris-(3-methylphenylphenylamino)triphenylamine ( m-MTDATA)/2- tert-butyl-9,10-di-beta-naphthylanthracene (TBADN)/2,9-dimethyl-4,7-diphenyl-1,10-phenan-throline (BCP)/LiF/Al, was fabricated, which show high efficient white electroluminescence (EL) or photovoltaic (PV) properties when it was driven by direct current (DC) bias or illuminated by ultraviolet (UV) light. Under a DC bias, the device shows efficient white EL emission. A maximum luminous efficiency of 1.1lm/W was obtained at 8V, which corresponds the Commission International de L’Eclairage coordinates (CIE) of ( x=0.298, y=0.365). When the bias was increased to 12V, the device shows bright white emission with the maximum brightness of 4300cd/m2, corresponding CIE coordinates of ( x=0.262, y=0.280). When the diode was irradiated by a 365nm UV-light (4mW/cm2), the open-circuit voltage ( Voc) of 1.2V, short-circuit ( Isc) of 0.065mA/cm2, fill factor (FF) of 0.24 and power conversion efficiency of 0.47% have been determined, respectively. The generation mechanisms of white light and PV of the bi-functional diode were discussed as well.
Keywords: White organic light emitting diode; Photovoltage; Bi-functional diode
Temperature dependence of the current–voltage characteristics of the Al/Rhodamine-101/p-Si(100) contacts by Ş. Karataş; C. Temirci; M. Çakar; A. Türüt (pp. 2209-2216).
The current–voltage ( I– V) characteristics of Al/Rhodamine-101/p-Si/Al contacts have been measured at temperatures ranging from 280 to 400K at 20K intervals. A barrier height (BH) value of 0.817eV for the Al/Rh101/p-Si/Al contact was obtained at the room temperature that is significantly larger than the value of 0.58eV of the conventional Al /p-Si Schottky diode. While the barrier height Φb0 decreases the ideality factors ( n) become larger with lowering temperature. The high values of n depending on the sample temperature may be ascribed to decrease of the exponentially increase rate in current due to space-charge injection into Rh101 thin film at higher voltage. Therefore, at all temperatures, it has been seen that the I– V characteristics show three different regions, the ohmic behavior at low voltages, and the space charge limited current with an exponential distribution of traps at high voltages.
Keywords: PACS; 73.61.Ph; 73.40.Lq; 73.40.Ns; 73.40.Ei; 73.30.+yOrganic semiconductor/inorganic semiconductor contacts; Heterojunction; Schottky contacts; Inhomogeneous barrier height; Rectification
Micropatterning of fluoropolymers by Penny S. Hale; Peter Kappen; Narelle Brack; Walaiporn Prissanaroon; Paul J. Pigram; John Liesegang (pp. 2217-2228).
Fluoropolymer (PTFE and FEP) substrates have been patterned through micro-contact printing of an aminosilane. The silane pattern was activated with a palladium catalyst that allowed the electroless deposition of copper which was used to form micropatterned copper electrodes. Conducting polymer micropatterns were then fabricated by electrodeposition of polypyrrole (PPy) onto the copper. The resulting patterns of 80μm and 10μm grids and 2μm and 5μm checkerboards were characterized using imaging XPS, TOF-SIMS, AFM and SEM. The size and resolution of the smallest copper patterns were limited by the copper grain size created during electroless deposition. The polypyrrole patterns were also limited by the roughness of the electrolytically deposited polymer film.
Keywords: PACS; 33.60.Fy; 07.79.Lh; 82.80.Rt; 81.15.Pq; 82.35.CdPolypyrrole; PDMS; Silane; Copper; Micro-contact printing; Micropatterning; XPS; AFM; TOF-SIMS
Macroporous fluoropolymeric films templated by silica colloidal assembly: A possible route to super-hydrophobic surfaces by Jian Li; Jun Fu; Yang Cong; Yang Wu; Longjian Xue; Yanchun Han (pp. 2229-2234).
A super-hydrophobic surface was obtained on a three-dimensional (3D) polyvinylidene fluoride (PVDF) macroporous film. The porous films were fabricated through self-assembled silica colloidal templates. The apparent water contact angle of the surface can be tuned from 106° to 153° through altering the sintering temperature and the diameter of the colloidal templates. A composite structure of micro-cavities and nanoholes on the PVDF surface was responsible for the super-hydrophobicity. The wettability of the porous surfaces was described by the use of the Cassie–Baxter model and Wenzel's equation.
Keywords: Super-hydrophobicity; Water repellent; Polyvinylidene fluoride; PVDF; Colloidal crystal; Opal; Macroporous materials
Preparation and characterization of core/shell particles with siloxane in the shell by Bailing Liu; Xiaobo Deng; Shunsheng Cao; Songjun Li; Rong Luo (pp. 2235-2241).
The core/shell particles consisting of polystyrene core and 3-(methacryloxypropyl)-trimethoxysilane (MPS) shell were prepared in the present study by successive seeding polymerization under kinetically controlled conditions and were characterized by particle size analyser, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The TEM image indicated that the particles containing organic siloxane presented an evident core/shell structure. Additionally, the study of XPS also revealed that MPS could be grafted onto the surface of polystyrene microspheres and the atomic ratio of C/Si on the surface of the core/shell particles (MPS-40) was very close to the ratio of C/Si in the molecule of MPS. The surface properties of the films produced from the core/shell particles were also investigated by the static contact angle method. Compared with the homopolymer of PS, the core/shell particles were more effective to create hydrophobic surface, so, the introduction of MPS was capable of obvious increase in water repellency.
Keywords: Core/shell particles; Polystyrene; Siloxane
Repetitive laser pulse heating analysis: Pulse parameter variation effects on closed form solution by M. Kalyon; B.S. Yilbas (pp. 2242-2250).
Laser conduction limited heating finds wide application in surface processing industry. Modelling of the heating process gives insight into the physical processes involved in conduction limited heating. Moreover, analytical solutions provide functional relation among the parameters that influence the heating process. In the present study, repetitive laser pulse heating of a solid substrate is considered. A closed form solution for the temperature rise including the cooling cycle is obtained using a Laplace transformation method. It is found that the results obtained from the closed form solution agree well with the numerical predictions. The maximum surface temperature rises rapidly once the cooling period between the consecutive pulses reduces.
Keywords: Laser; Conduction; Pulse heating; Closed form
Preparation and characterization of iron oxide thin films by spray pyrolysis using methanolic and ethanolic solutions by J.D. Desai; H.M. Pathan; Sun-Ki Min; Kwang-Deog Jung; Oh-Shim Joo (pp. 2251-2258).
Iron oxide thin films have been obtained by spray pyrolysis using 100% methanolic and ethanolic solutions of iron tri-chloride. The films were deposited onto ITO-coated glass substrates. The preparative conditions have been optimized to obtain compact, pin-hole-free and smooth thin films which are adherent to the substrate. The structural, morphological and compositional characterizations have been carried out by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The films deposited using ethanolic solution results into pure hematite; α-Fe2O3 thin films, however, films deposited using methanolic solution consists of hematite and maghemite-c phases of iron oxide. The films are nanocrystalline with particle size of 30–40nm. The optical absorbance of the film was of the order of 105cm−1. The optical band gap of films was found to be 2.26 and 2.20eV for the films deposited using methanolic and ethanolic solutions, respectively.
Keywords: Iron oxide; Thin Film; Spray pyrolysis; Preparation and characterization
Reactive sputtering TiO2 films for surface coating of poly(dimethylsiloxane) by Zhiqiang Niu; Xiaoyu Jia; Weiping Zhang; Wenyuan Chen; KaiYou Qian (pp. 2259-2264).
Titanium dioxide (TiO2) films were prepared on poly(dimethylsiloxane) (PDMS) substrate by direct current (DC) reactive sputtering to change surface physical properties of PDMS. The effects of the changes were investigated by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) analysis, water contact angle measurements and protein adsorption tests. Improved wettability and reduced adsorption properties were observed on PDMS surface coated TiO2 films.
Keywords: PDMS; TiO; 2; films; Reactive sputtering; Surface coating; XPS; Contact angle; Protein adsorption
Cold plasma-induced modification of the dyeing properties of poly(ethylene terephthalate) fibers by Antonino Raffaele-Addamo; Elena Selli; Ruggero Barni; Claudia Riccardi; Francesco Orsini; Giulio Poletti; Laura Meda; Maria Rosaria Massafra; Bruno Marcandalli (pp. 2265-2275).
Surface modification of poly(ethylene terephthalate) (PET) fabrics induced by air radiofrequency (RF) plasma treatment has been investigated systematically as a function of plasma device parameters, to identify the plasma–polymer surface interactions prevailing under different operating conditions and leading to an increased color depth upon dyeing. Some tests have also been performed employing chemically inert argon as a feedstock gas. The dyeing properties of plasma-treated fibers were correlated to their topographical characteristics, determined by AFM analysis, and to their chemical surface composition, determined by XPS analysis, while the plasma-originated UV radiation was found to have no relevant effects in PET surface modification. The relative importance of plasma-induced surface processes, such as etching and grafting of polar species, is discussed in relation to their role in modifying PET dyeing properties.
Keywords: PACS; 52.75.R; 61.16.C; 79.60Air and Ar plasma treatment; Poly(ethylene terephthalate) fibers; Dyeing; AFM; XPS
Initial oxidation of Mn surface studied by ultraviolet photoelectron spectroscopy and metastable induced electron spectroscopy by B. Lescop (pp. 2276-2280).
Metastable induced electron spectroscopy (MIES) was combined to ultraviolet photoelectron spectroscopy (UPS) to study the initial steps of manganese oxidation. Oxygen exposure directly led to the formation of MnO with no intermediate states. The MnO feature saturation observed by MIES and UPS techniques showed noticeable differences and proved the formation of several oxide layers. The oxidation kinetics was studied by measuring MnO features by UPS, which depend on the surface coverage by oxygen. We observe a decrease of oxygen adsorption probability with oxygen exposure. Oxidation proceeds by oxygen dissolution into the first layers to form a three-dimension MnO. This hypothesis was confirmed by our work function measurements.
Keywords: PACS; 71.30.+h; 81.65.Mq; 82.65.+rManganese; Photoelectron spectroscopy; Metastable induced electron spectroscopy (MIES); Oxidation; Thin film growth
Self-diffraction and Z-scan studies in organic dye doped thin films by R. Madhana Sundari; P.K. Palanisamy (pp. 2281-2287).
Self-diffraction in Acid Red 87 (eosin Y) dye doped thin films is studied using argon ion laser (514.5nm). Growth of self-diffraction grating is monitored by measuring intensities of various diffraction orders. This study has resulted in the observation of phase variation between the contributing beams in any diffracted order. This change of phase is measured at various stages of grating formation. Due to self-phase modulation, circular concentric rings pattern is obtained in the far field. The observed fluctuation in this pattern may be due to the phase variation between the contributing beams in any diffracted order. Z-scan technique is used to study the optical non-linearity of the sample.
Keywords: PACS; 42.70 Jk; 42.70 NqDye doped thin films; Self-diffraction; Z-scan technique; Saturation absorption; Non-linear optical materials
SIMS direct surface imaging of Cu1− xCr x formation by A. Lamperti; P.M. Ossi (pp. 2288-2296).
Cu–Cr alloys, irradiated with a low-energy, high-current electron beam, are analyzed by high-resolution secondary ion mass spectrometry. Mass spectra and images of Cu+ and Cr+ surface distributions finely reveal the regions enriched in Cu and Cr. For electron beam energies above a threshold value, the formation of a non-equilibrium Cu1− xCr x solid solution, extending over sub-micrometer areas is highlighted for the first time. A discussion of the process leading to Cu1− xCr x formation is given.
Keywords: PACS; 61.80.Fe Electrons and positron radiation effects; 61.82.Bg Metals and alloys; 82.80.Ms Mass spectrometry (including SIMS, …); 64.60.My Metastable phasesElectron bombardment; Secondary ion mass spectroscopy; Copper; Chromium; Compound formation
Uniformity analysis of dielectric barrier discharge (DBD) processed polyethylene terephthalate (PET) surface by Chaozong Liu; Norman M.D. Brown; Brian J. Meenan (pp. 2297-2310).
A dielectric barrier discharge (DBD) plasma, operating in air at atmospheric pressure, has been used to induce changes in the surface properties of polyethylene terephthalate (PET) films. The effects that the key DBD operating parameters: discharge power, processing speed, processing duration, and electrode configurations, have on producing wettability changes in the PET surface region have been investigated. The approach taken involves the application of an Taguchi experimental design and robust analysis methodology. The various data sets obtained from these analyses have been used to studies the effect of the operating parameters on the surface uniformity and efficiency of the said treatment.In general, the results obtained indicate that DBD plasma processing is an effective method for the controlled surface modification of PET. Relatively short exposures to the atmospheric pressure discharge produces significant wettability changes at the polymer film surface, as indicted by pronounced reductions in the water contact angle measured. It was observed that the wettability of the resultant surface shows no significant differences in respect to orientation parallel (L-direction) or perpendicular (T-direction) to the electrode long axis. However, there was significant differences between the data obtained from these two orientations. Analysis of the role of each of the operating parameters concerned shows that they have a selective effectiveness with respect to resultant surface modification in terms of uniformity of modification and wettability. The number of treatment cycles and the electrode configuration used were found to have the most significant effects on the homogeneity of the resultant PET surface changes in L- and T-orientation, respectively. On the other hand, the applied power showed no significant role in this regard. The number of treatment cycles was found to be the dominant factor (at significance level of 0.05) in respect of water contact angle changes at the processed PET surface in both orientations. The driven metal electrodes (stainless steel or aluminium) were apparently superior to the driven dielectric electrode (ceramic or quartz) configurations. The grounded electrode in each case was a silicon rubber-covered aluminium plate (see later). The nature and scale of the surface changes that originate from the various processing conditions employed have been considered so as to determine the optimum treatment conditions in respect of processing outcomes, properties and any orientation dependence. Thus, it was revealed that higher processing speeds and longer processing durations are key for uniformity along the electrode axial orientation, while lower processing speeds and short exposure durations are key considerations, in the corresponding perpendicular orientation. In general, longer processing durations (low processing speeds and a high number of treatment cycles) and higher plasma powers induced greater changes in the surface wettability of the PET, as demonstrated by the observed water contact angles. This behaviour is taken to indicate that different combinations of DBD operating parameters and electrodes produce discharge conditions that can result in different plasma chemical processes in respect of uniformity, treatment efficiency and orientation dependence.
Keywords: Surface modification; Dielectric barrier discharge; Atmospheric plasma processing; Polyethylene terephthalate (PET); Robust analysis
The corrosion behaviour of polypyrrole coating synthesized in phenylphosphonic acid solution by T. Tüken; B. Yazıcı; M. Erbil (pp. 2311-2318).
Electrochemical synthesis of polypyrrole (PPy) film was achieved on mild steel (MS), in monomer containing 0.1M phenylphosphonic acid solution. The synthesis was carried out using cyclic voltammetry technique. It was found that the electrode surface could only become completely passive, after a few successive cycles in solution of 0.1M pyrrole+0.1M phenylphosphonic acid. Then, the thickness of polymer film was increased with help of successive cycles in a relatively narrower potential range. The corrosion performance of polymer coating was investigated in 3.5% NaCl solution, using electrochemical impedance spectroscopy (EIS) and anodic polarization curves. It was shown that the coating had high stability and low permeability, under such aggressive conditions. The EIS results also showed that the coating exhibited important anodic protection behaviour on mild steel. The percent protection efficiency value ( E%) was found to be 98.4% and the percent total porosity value ( P%) was determined to be 0.752%, after 96h exposure time to corrosive solution.
Keywords: Polypyrrole; Phenylphosphonic acid; Corrosion; ac impedance
Determination of the debris produced from poly(ethylene terephthalate) during KrF excimer laser ablation by Dong Sig Shin; Jae Hoon Lee; Jeong Suh; To Hoon Kim (pp. 2319-2327).
Pulsed UV laser beams, which are widely used in the processing of polymers, have many advantages because their photon energy is higher than the binding energy of polymers. Fabricating polymers with a UV laser process is faster, cleaner, and more convenient than with other processes. Nevertheless, some problems occur in the precision microprocessing of polymers. For example, the formation and deposition of surface debris, which is produced from the breakdown of either polymer chains or radical bonds.To determine the formation and origin of surface debris, a KrF excimer laser beam (248nm) was used in the processing of poly(ethylene terephthalate) (PET). The investigation of the debris formation was facilitated by UV–vis spectroscopy, ATR FT-IR spectroscopy, and NMR spectroscopy. The UV–vis absorption peak indicates that the primary chromophore in the PET is benzoate. Furthermore, because benzoate causes the primary absorption, the absorbed energy is transferred by heat generation to an unsaturated ester. The ATR FT-IR spectrometer measurements show that the phenyl systems in the benzoate are demolished by ablation. This phenomenon indicates that the photochemical reaction causes the benzoate bonds to break down, and this breakdown in turn causes the carbonization to leave debris on the PET.
Keywords: KrF excimer laser; Laser ablation; Surface debris; Poly(ethylene terephthalate); Chromophore; UV–vis spectroscopy; ATR FT-IR spectroscopy; NMR spectroscopy
Photoluminescence spectroscopy study on tris(8-hydroxyquinoline) aluminum film by Y.F. Xu; H.J. Zhang; H.Y. Li; S.N. Bao; P. He (pp. 2328-2333).
In situ photoluminescence spectroscopy (PL) measurements of tris(8-hydroxyquinoline) aluminum (Alq3) film were carried out. Upon deposition of Alq3 on the glass substrate, the PL intensity changes dramatically, while the peak position of Alq3 emission shows a sharp red-shift from 524nm at the initial deposition of Alq3, and tends to a saturation value of 536nm for the film thickness range from 2 to 500nm. This red-shift is associated with the change from the 2D to 3D exciton state with increasing Alq3 film thickness. Temperature dependent PL spectra of Alq3 films showed, besides the changes in the PL intensity, clearly a blue-shift of Alq3 emission about 9nm for the film annealing up to 150°C, while no any shift of Alq3 emission was observed for the film annealing below 130°C. Both changes in PL intensity, and especially in the peak position of Alq3 emission were attributed to crystallization (thermal) effect of Alq3 film upon annealing.
Keywords: PACS; 78.66.Qn; 78.55.Kz; 81.40.TvTris(8-hydroxyquinoline) aluminum; Thin film; Photoluminescence; Thermal treatment
Chemical and microstructural study of the oxygen passivation behaviour of nanocrystalline Mg and MgH2 by O. Friedrichs; J.C. Sánchez-López; C. López-Cartes; M. Dornheim; T. Klassen; R. Bormann; A. Fernández (pp. 2334-2345).
Nanocrystalline Mg and MgH2 samples have been prepared by high-energy ball milling and gas phase condensation methods. Starting from these materials in their “as received� state without air exposure, a study of the oxygen and air passivation behaviour was carried out by “in situ� analysis of the samples by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The binding energy and photoemission Auger parameters have been determined for metallic magnesium as well as for magnesium hydride, oxide and hydroxide species. Values of the MgH2 material were reported for the first time. The study clearly shows the formation of an oxide passivation layer of ca. 3–4nm in thickness for all the nanocrystalline magnesium samples handled under controlled inert gas atmospheres. A hydroxide like amorphous layer is formed at the topmost surface layers of the nanocrystalline Mg and MgH2 samples. The implication of these studies for H2 storage and transport applications of nanocrystalline magnesium is discussed.
Keywords: PACS; 79.60.–i; 81.65.Mg; 81.20.Wk; 68.37.–d; 81.07.BcNanocrystalline magnesium; Mechanical milling; Oxidation; XPS; TEM
Spatially resolved Raman spectroscopy evaluation of residual stresses in 3C-SiC layer deposited on Si substrates with different crystallographic orientations by W.L. Zhu; J.L. Zhu; S. Nishino; G. Pezzotti (pp. 2346-2354).
Raman scattering studies were performed on hot-wall chemical vapor deposited (heteroepitaxial) silicon carbide (SiC) films grown on Si substrates with orientations of (100), (111), (110) and (211), respectively. Raman spectra suggested that good quality cubic SiC single crystals could be obtained on the Si substrate, independent of its crystallographic orientation. Average residual stresses in the epitaxially grown 3C-SiC films were measured with the laser waist focused on the epilayer surface. Tensile and compressive residual stresses were found to be stored within the SiC film and in the Si substrate, respectively. The residual stress exhibited a marked dependence on the orientation of the substrate. The measured stresses were comparable to the thermal stress deduced from elastic deformation theory, which demonstrates that the large lattice mismatch between cubic SiC and Si is effectively relieved by initial carbonization. The confocal configuration of the optical probe enabled a stress evaluation along the cross-section of the sample, which showed maximum tensile stress magnitude at the SiC/Si interface from the SiC side, decreasing away from the interface in varied rate for different crystallographic orientations. Defocusing experiments were used to precisely characterize the geometry of the laser probe in 3C-SiC single crystal. Based on this knowledge, a theoretical convolution of the in-depth stress distribution could be obtained, which showed a satisfactory agreement with stress values obtained by experiments performed on the 3C-SiC surface.
Keywords: PACS; 81.15.Gh; 87.64.JeRaman spectroscopy; CVD; 3C-SiC; Stress evaluation
Multiple roles of bathocuproine employed as a buffer-layer in organic light-emitting diodes by Yuan-Min Wang; Feng Teng; Qing-Cheng Zhou; Yong-Sheng Wang (pp. 2355-2359).
Efficiency and brightness and carriers injection have been obviously improved by using bathocuproine (BCP) as a buffer-layer in organic light-emitting diodes. Compared with the bufferless device, the quantum efficiency of device ITO/NPB (10nm)/Alq3 (10nm)/BCP (2.4nm)/Al has increased four times at the same current density (32mA/cm2). Moreover, the buffer layer has changed the current-voltage properties and the turn-on voltage has obviously decreased. Considering BCP and Al3+ can react conveniently under room temperature, we suggest that a complex cathode structure of BCP/[(Al) x(BCP) y]3 x+/Al has formed under electric field and the new cation [(Al) x(BCP) y]3 x+ at the BCP/Al interface has improved the internal electric field and then enhanced the electrons injection. we conclude that: for a very thin (<1nm) BCP buffer layer, improving electron injection will principally responsible to the improvement of the performance of the OLEDs; for a thicker BCP layer, there will be a synthetic function of BCP: improving electron injection, hole-blocking and electron-transporting.
Keywords: Bathocuproine; Buffer-layer; Organic light-emitting diodes
Modification of alumina barrier-layer through re-anodization in an oxalic acid solution with fluoride additives by ArÅ«nas Jagminas; Marija KurtinaitienÄ—; Renato Angelucci; Gintaras ValinÄ?ius (pp. 2360-2367).
A new simple method for modification of the porous alumina barrier-layer is described and characterized by the voltammetric, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) techniques. The method is based on re-anodization of porous alumina under galvanostatic conditions in the anodizing bath that, in addition to conventional anodization solution components, contains fluoride salts: (NH4)2SiF6 or NH4F. During first few minutes of alumina re-anodization, the sharp drop of anodizing voltage was observed, which is indicative of chemical/electrochemical transformations of the alumina barrier-layer. As a result, the scalloped structure of the barrier-layer changes drastically, becoming smooth and finely grained. Upon re-anodization, a significant loss of insulating ability of the barrier-layer and considerable increase in its capacitance were observed, while the variation of the constant phase element was found to be consistent with the oxide film morphology transformations observed by microscopy techniques. All these changes intensify with fluoride concentration increase. Curiously, (NH4)2SiF6 exhibited about three-fold stronger effect on the barrier-layer properties than NH4F, thus allowing us to hypothesize about possible chemical break up of SiF62− anion and the formation of the AlF3 phase inside the alumina pores.
Keywords: PACS; 42.15.Eq; 82.45.Cc; 73.40; 84.37.+qAl anodization; Interfaces; SEM; TEM; EIS
Study on corrosion properties of pipelines in simulated produced water saturated with supercritical CO2 by Z.D. Cui; S.L. Wu; S.L. Zhu; X.J. Yang (pp. 2368-2374).
This work aims at systematically investigating the corrosion properties of three pipeline steels in static simulated produced water (SPW) saturated with supercritical carbon dioxide using weight-loss tests. SEM, XRD and XPS were employed to study the chemical composition and structure of the corroded surface. The results showed that the corrosion rates of the tested steels significantly decreased with increasing the exposure temperature and time in static SPW saturated with SC-CO2. The surface film on the corroded surface, which markedly influenced the CO2 corrosion behavior of the samples, was mainly composed of (Fe, Ca)CO3 and α-FeOOH. Inhomogeneous element distribution of carbon, oxygen, calcium and iron in the surface film was observed. (Fe, Ca)CO3 formed at a lower temperature was more stable than that formed at elevated temperatures.
Keywords: PACS; 82.45Supercritical carbon dioxide; CO; 2; corrosion; Pipeline; Surface film
Thickness determination of thin and ultra-thin SiO2 films by C-AFM IV-spectroscopy by Werner Frammelsberger; Guenther Benstetter; Janice Kiely; Richard Stamp (pp. 2375-2388).
Conductive atomic force microscopy was used to determine the electrical oxide thickness for five different silicon dioxide layers with thickness in the order of 1.6–5.04 nm. The electrical thickness results were compared with values determined by ellipsometry. A semi-analytical tunnelling current model with one single parameter set was used to superpose current/voltage curves in both the direct tunnelling and the Fowler–Nordheim tunnelling regime regions. The overall electrical oxide thickness was determined by statistical means from results of nearly 3000 IV-curves recorded for different conductive CoCr-coated tips. Good agreement between the shape of model and experimental data was achieved, widely independent of the oxide thickness. Compared with the ellipsometry value, the electrical thickness was larger by a value of 0.36 nm (22%) for the thinnest oxide and smaller by a value of 0.31 nm (6%) for the thickest oxide, while intermediate values yielded differences better than 0.15 nm (<6%). The physical differences between the measurement techniques were shown to contribute to this observation. In addition, statistical deviations between single and multiple measurements using a single tip and using a number of different tips were analysed. The causes, for example, natural oxide thickness variations, tip wear, air humidity induced effects and contaminations, are evaluated and discussed. The method proposed was able to determine the electrical oxide thickness with a standard deviation in the order of±6–9%. The results suggest that for optimal results it is necessary to perform several repetitions of IV-measurements for one sample and, in addition, to employ more than one tip.
Keywords: PACS; 73.40.QvAFM; C-AFM; MOS; Silicon dioxide; Tunnelling
The inhibited effect of some tetrazolic compounds towards the corrosion of brass in nitric acid solution by M. Mihit; S. El Issami; M. Bouklah; L. Bazzi; B. Hammouti; E. Ait Addi; R. Salghi; S. Kertit (pp. 2389-2395).
The effect of the addition of some tetrazolic type organic compounds: 1-phenyl-5-mercapto-1,2,3,4-tetrazole (PMT), 1,2,3,4-tetrazole (TTZ), 5-amino-1,2,3,4-tetrazole (AT) and 1-phenyl-1,2,3,4-tetrazole (PT) on the corrosion of brass in nitric acid is studied by weight loss, polarisation and electrochemical impedance spectroscopy (EIS) measurements. The explored methods gave almost similar results. Results obtained reveal that PMT is the best inhibitor and the inhibition efficiency ( E%) follows the sequence: PMT>PT>AT>TTZ. Polarization measurements also indicated that tetrazoles acted as mixed-type inhibitors without changing the mechanism of the hydrogen evolution reaction. Partial π-charge on atoms has been calculated. Correlation between the highest occupied molecular orbital energy EHOMO and inhibition efficiencies was sought. The adsorption of PMT on the brass surface followed the Langmuir isotherm. Effect of temperature is also studied in the (25–50°C) range.
Keywords: Copper alloys; Nitric acid; Corrosion; Inhibition; Tetrazole
Effect of boron paste thickness on the growth kinetics of polyphase boride coatings during the boriding process by I. Campos; R. Torres; O. Bautista; G. Ramírez; L. Zúñiga (pp. 2396-2403).
The growth kinetics of FeB and Fe2B phases forming on AISI M2 steel by paste boriding was studied using different values of paste thickness, treating temperature and exposure time. The growth of iron boride layers is described by the mass balance equation between phases in thermodynamic equilibrium, assuming that the boron concentration at the interfaces remain constant during the treatment. The experimental results show that boron mobility and growth kinetics of iron borides are considerably increased when the paste thickness is increased at constant values of temperature and exposure time.
Keywords: Growth models; Diffusion; Boriding; Paste boron
Ammonia sensing characteristics of ZnO nanowires studied by quartz crystal microbalance by Xiaohua Wang; Jian Zhang; Ziqiang Zhu (pp. 2404-2411).
The ZnO nanowires have been prepared and studied as the sensing element for the detection of ammonia. The ZnO nanowires were first synthesized by evaporating high purity zinc pellets at 900°C and then distributed onto the electrode surfaces of quartz crystals at room temperatures. Gas sensitive properties of ZnO nanowires layer were studied in terms of the quartz crystal microbalance (QCM) at room temperature. It is found that the obtained response of the sensors varied with the thickness of the ZnO nanowires layer. ZnO nanowires showed high sensitivity to ammonia in the range of 40–1000ppm. The response time of the sensor was as fast as ∼5s at any concentration (40–1000ppm) of ammonia gas. The ZnO nanowires-coated sensors have a good frequency stability and reproducibility. All results demonstrated that the ZnO nanowire was a potential gas sensing material for practical use.
Keywords: ZnO nanowires; Quartz crystal microbalance; Gas sensor; Frequency shift; Ammonia
Microstructural inhomogeneity in plasma-sprayed hydroxyapatite coatings and effect of post-heat treatment by Yu-Peng Lu; Gui-Yong Xiao; Shi-Tong Li; Rui-Xue Sun; Mu-Sen Li (pp. 2412-2421).
The microstructural inhomogeneity in the plasma-sprayed hydroxyapatite (HA) coatings was characterized by using electron probe microanalyser (EPMA). A simple and artful method was developed to detect the interface characteristics. All the samples for observation were ground and polished along the direction parallel to the coating surfaces. The BSE images directly and clearly showed the inhomogeneity in the as-sprayed coatings with the amorphous regions being bright gray and crystalline regions being dark gray. X-ray diffractometer (XRD) patterns indicated that after immersion in deionized water for 20 days, bone-like apatite and α-Ca2P2O7 precipitated on the polished surfaces of the as-sprayed HA coatings. The post-heat treatment could eliminate the microstructural inhomogeneity in the coatings. Only β-Ca2P2O7 precipitated on the surfaces of the heat-treated HA coatings. The immersed samples were re-polished till tiny substrate was bared to investigate the effect of immersion on interface. It was shown that the immersion decreased the cohesive strength of the as-sprayed coatings. There were more and broader cracks in the splats that came into contact with the substrate and amorphous phase increased toward the coating–substrate interface. Post-heat treatment was proved to reduce the peeling off of coating during re-polishing operation. It was proposed that the distributions of amorphous phase and cracks in as-sprayed coatings are detrimental to coating properties and should be modified through improving the plasma spraying processing.
Keywords: PACS; 81.15.R; 81.05Hydroxyapatite; Coatings; Microstructural inhomogeneity; Plasma spraying; Heat treatment
Characterization of the unstability of 4-mercaptoaniline capped platinum nanoparticles solution by combining LB technique and X-ray photoelectron spectroscopy by Frédéric Raynal; Arnaud Etcheberry; Sara Cavaliere; Vincent Noël; Henri Perez (pp. 2422-2431).
This paper reports on the study of the evolution of 4-mercaptoaniline ( p-HSC6H4NH2) functionalized platinum nanoparticles in solution by coupling the Langmuir–Blodgett technique and X-ray photoelectron spectroscopy (XPS). The spectra are recorded on mixed LB films containing fatty acid and platinum particles in proportion 50/50. Several samples built from fresh and aged solutions of particles are analyzed. Comparison of the Pt 4f, S 2p and N 1s regions in each case points to the time dependant chemical evolution of the functionalized particles involving at once platinum, thiolate and amine components. The particle aging in solution is reported during several months, until the complete flocculation of the functionalized platinum nanoparticles. Using the compared XPS analysis of the LB layers obtained from the different particle solutions, unstability of the storage looks then clearly related to the chemical evolution of the bifunctional organic crown.
Keywords: Platinum nanoparticles; Functionalization; Langmuir–Blodgett technique; XPS
Effects of evolving surface morphology on yield during focused ion beam milling of carbon by D.P. Adams; T.M. Mayer; M.J. Vasile; K. Archuleta (pp. 2432-2444).
We investigate evolving surface morphology during focused ion beam bombardment of C and determine its effects on sputter yield over a large range of ion dose (1017–1019ions/cm2) and incidence angles ( Θ=0–80°). Carbon bombarded by 20keV Ga+ either retains a smooth sputtered surface or develops one of two rough surface morphologies (sinusoidal ripples or steps/terraces) depending on the angle of ion incidence. For conditions that lead to smooth sputter-eroded surfaces there is no change in yield with ion dose after erosion of the solid commences. However, for all conditions that lead to surface roughening we observe coarsening of morphology with increased ion dose and a concomitant decrease in yield. A decrease in yield occurs as surface ripples increase wavelength and, for large Θ, as step/terrace morphologies evolve. The yield also decreases with dose as rippled surfaces transition to have steps and terraces at Θ=75°. Similar trends of decreasing yield are found for H2O-assisted focused ion beam milling. The effects of changing surface morphology on yield are explained by the varying incidence angles exposed to the high-energy beam.
Keywords: PACS; 81.65.C; 79.20.R; 34.50.DSputter yield; Surface morphology; Ripple morphology