Grazing Angle X-ray Diffraction Research Articles

Effect of sputter power on red-shifted optoelectronic properties in magnetron sputtered Ag/ZnO thin films

This study explores Ag/ZnO thin films on glass (Corning 0211) substrates, which were deposited using dc/rf magnetron reactive sputtering at varying Ag-sputter powers. The impact of Ag-sputter power on physical properties, such as structural, surface, compositional, optical, and electrical properties, is systematically explored. Grazing angle x-ray diffraction affirms a single-phase hexagonal wurtzite ZnO structure in all films, predominantly oriented along (002) normal to the substrate. Thin films deposited at 90 W Ag-sputter power exhibit superior structural and morphological properties, including greatest crystallite and grain size, minimum stress, and roughness. Electrical studies indicate that the material exhibits a semiconducting nature, with its electrical resistivity decreasing to a minimum of 0.8 Ω cm at 95 W. At this level of Ag sputter power, the films demonstrate low resistivity, high mobility (0.49 cm2/V s), a charge carrier concentration of 9.6 × 1019 cm−3, and an optical transmittance of 79%, along with an optical band gap energy (Eg) of 3.06 eV. This underscores the influence of Ag sputter power in tailoring Ag/ZnO thin films for optoelectronic applications.

Influence of aluminum addition on structure, hardness, and oxidation resistance of Ta1−xAlxN thin films

Ta1−xAlxN thin films with 5, 15, and 40 at.% Al addition were co‐deposited by reactive magnetron sputtering and characterized by Rutherford backscattering spectroscopy (RBS), grazing angle X‐ray diffraction (GAXRD), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nanohardness, and oxidation tests. GAXRD and XPS analyses showed, regardless of the % Al added, the non‐existence of ternary nitride Ta1−xAlxN, but always as individual binary nitrides, TaN and AlN. Sample TaAlN_15 obtained the highest hardness and H3/E2 values, possibly due to the AlN grains presence, which were efficient in distorting the TaN lattice. All samples failed oxidation tests at 873 K, showing that the Al addition was not efficient in improving this property for tantalum aluminum nitride thin films.

Ceramic conversion treated titanium implant abutments with gold for enhanced antimicrobial activity

IntroductionPeri-implantitis is an inflammatory process around dental implants that is characterised by bone loss that may jeopardize the long-term survival of osseo integrated dental implants. The aim of this study was to create a surface coating on titanium abutments that possesses cellular adhesion and anti-microbial properties as a post-implant placement strategy for patients at risk of peri-implantitis. Materials and MethodsmethodsTitanium alloy Grade V stubs were coated with gold particles and then subjected to ceramic conversion treatment (CCT) at 620 °C for 3, 8 and 80 h. The surface characteristics and chemistry were assessed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. The leaching profile was investigated by inductively coupled plasma mass spectroscopy (ICP-MS) for all groups after 7, 14 and 28 days in contact with distilled water. A scratch test was conducted to assess the adhesion of the gold coating to the underlying titanium discs. Two bacterial species (Staphylococcus aureus (SA) &Fusobacterium nucleatum (FN)) were used to assess the antibacterial behaviour of the coated discs using a direct attachment assay test. The potential changes in surface chemistry by the bacterial species were investigated by grazing angle XRD. ResultsThe gold pre-coated titanium discs exhibited good stability of the coating especially after immersion in distilled water and after bacterial colonisation as evident by XRD analysis. Good surface adhesion of the coating was demonstrated for gold treated discs after scratch test analysis, especially titanium, following a 3-hour (3 H) ceramic conversion treatment. All coated discs exhibited significantly improved antimicrobial properties against both tested bacterial species compared to untreated titanium discs. ConclusionsCeramic conversion treated titanium with a pre-deposited gold layer showed improved antimicrobial properties against both SA and FN species than untreated Ti-C discs. Scratch test analysis showed good adherence properties of the coated discs the oxide layer formed is firmly adherent to the underlying titanium substrate, suggesting that this approach may have clinical efficacy for coating implant abutments.

Synthesis and characterization of ZnO tetrapod-like nanorods without catalyst by wet thermal evaporation and applied on dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) continue to attract as one of the most important renewable energy technologies due to their simple production, environmentally friendly, and lower-cost fabrication process compared to the most common types of solar cells. Zinc oxide (ZnO) nanostructures have motivated researchers to fabricate DSSCs as photo-anodes due to their unique properties, such as different types of structures, appropriate optical properties, proper energy bandgap, and high electron transfer characteristics. This article reports the simple preparation of ZnO tetrapod-like nanorods using the wet thermal evaporation method on porous silicon substrate PS/Si and applied as a photoanode on DSSCs. ZnO nanostructures were characterized by using grazing-angle X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) measurements. A significant difference in the performance of DSSCs has been investigated by using a standard dye di-tetrabutylammonium cis–bis(isothiocyanate)bis(2,2[Formula: see text]-bipyridyl-4,4[Formula: see text]-dicarboxylato) ruthenium (II) (N719) reloaded on ZnO tetrapod-like nanorods ([Formula: see text], [Formula: see text], [Formula: see text]%, and [Formula: see text]%) being more efficient than the ZnO spherical nanoparticles as a reference solar cell ([Formula: see text], [Formula: see text], [Formula: see text]%, and [Formula: see text]%).

Improving the corrosion and wear resistance of CoCrNiSi0.3 Medium-Entropy Alloy by magnetron sputtered (CrN/Cr)x multilayer films

In this study, a medium entropy alloy (MEA) system consisting of Co, Cr, and Ni was selected to incorporate Si, resulting in the creation of CoCrNiSi0.3 MEA. The surface was coated with (CrN/Cr)x multilayer films to improve wear and corrosion resistance. The hardness, wear, corrosion, and nanoindentation tests were used to analyze the characteristics of CrN/Cr multilayer films and their protective performance. Low grazing angle X-ray diffraction (GIXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), water contact angle analyzer, and transmission electron microscopy (TEM) were utilized to investigate the composition and structure of (CrN/Cr)x multilayer films. The intermediate Cr layer inhibits the columnar growth of the CrN layers and is progressively refined as the number of CrN/Cr bilayers increases. The Cr layer exhibits superior toughness in the multilayer structure and effectively hinders crack propagation. Therefore, the (CrN/Cr)3 multilayer film has the most outstanding anti-wear performance. The wear rates under 2 N and 4 N loads are 3.331 × 10−6 mm3•m−1•N−1 and 1.124 × 10−5 mm3•m−1•N−1, respectively. The growth of columnar crystals is suppressed and a more compact multilayer film is formed, resulting in a reduction in the defect density and an increase in the water contact angle, which retards the ingress of corrosive liquid and improves corrosion resistance. The corrosion current density of the (CrN/Cr)3 multilayer film is 0.73 μA•cm−2, while the corrosion polarization impedance is 962.35 Ω•cm2.

Selective fluoride ion sensing in aqueous medium using ultrathin film of functionalized single-walled carbon nanotubes

The presence of fluoride ion (F - ) in potable water above its permissible limit (1–4 ppm) poses serious health hazards. Hence, detection of fluoride in potable water is essential. The π-electron rich single-walled carbon nanotubes can interact with F- to form semi-covalent C-F bond which can act as a basis for F - sensing in aqueous medium. Here, a single layer of octadecylamine functionalized single-walled carbon nanotubes (ODA-SWCNTs) was transferred onto solid substrates by the Langmuir–Schaefer (LS) method and employed for sensing of F- in aqueous medium by recording piezo and electrochemical responses, simultaneously using an electrochemical quartz crystal microbalance. The lowest detectable concentration and range of detectable concentration of fluoride ion were found to be 0.5 ppm and 0.5–145 ppm, respectively. The analysis of the LS film of ODA-SWCNTs before and after interaction with fluoride ion by Raman spectroscopy and grazing angle x-ray diffraction measurement reveals perturbation of π-electrons of the SWCNTs due to semi-covalent binding of the fluoride with the carbon atom of the nanotubes. The sensor showed a good selectivity towards the F- in the presence of some heavy metal ions. Testing of the sensor towards F- in tap water obtained from some local region showed a good accuracy.

Comparative study of calcium phosphate deposition on nanotubular and sandblasted large grit acid-etched titanium substrates

Titanium and its alloys are widely used in biomedical applications due to their excellent properties such as biocompatibility, good corrosion resistance, low density, and high elastic modulus. However, their bioinert behavior often results in prolonged osseointegration periods. Therefore, surface modification techniques have been investigated to improve the bioactivity of titanium. In this study, the morphological and chemical properties of sandblasted, large grit, acid-etched (SLA), and nanotubular (NT) surfaces were investigated before and after the deposition of calcium phosphate (CaP) compounds by a chemical conversion method. Various techniques were used to characterize these surface modifications applied to titanium, including microhardness tests, atomic force microscopy, water contact angle measurements, scanning electron microscopy, grazing angle X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results showed that the SLA surface was rougher than the NT surface, and the hydrophilic behavior of both samples was enhanced after immersion in NaOH and chemical conversion. The higher concentration of Ca, P, and phosphate functional groups on the NT surface indicates that a greater amount of CaP was deposited on this surface. The CaP-modified NT surface exhibited a favorable surface topography and chemical composition, which may be advantageous for use in titanium dental implants. In addition, in vitro assays showed that the samples prepared here are promising candidates for biomedical use, as they exhibited high cell viability, non-toxicity, and osteogenic properties.

The diffusion coefficient of oxygen into alpha-uranium at 323 °K determined by grazing angle X-ray diffraction technique

The diffusion coefficient of oxygen into alpha-uranium at 323 °K determined by grazing angle X-ray diffraction technique

Lithium Dendrite Growth Suppression in Anode-Free Lithium Battery Using Bifunctional Electrospun Gel Polymer Electrolyte Membrane

Anode free Li metal battery (AFLMB) are being intensively investigating in recent years as a means to achieve higher capacity when compared with standard Li metal batteries. However, the severe electrolyte decomposition during plating/stripping cycles, that causes fast Li dendrite growth and quick capacity fading, is challenging for its commercialization. Herein, poly (vinylidene fluoride-hexafluoropropylene) polymer containing Li1.6Al0.4Mg0.1Ge1.5(PO4)3 ceramic filler (90:10 w% ratio, PVDF-HFP-10) gel polymer electrolyte (GPE) is employed for the first time in AFLMB to suppress the Li dendrite growth and homogeneous Li deposition is achieved during Li metal plating/stripping. The PVDF-HFP-10 based membrane is manufactured using electrospinning technique, which is well known and effective technique to increase the amount of crystalline β-phase of PVDF-HFP, on Cu collector foil. Particularly, a pure crystalline β-phase of PVDF-HFP has been observed in the adhesion layer sticked with Cu collector as confirmed from the analysis of Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy measurements. The adhesion layer is further investigated using X-ray absorption spectroscopy (XAS), grazing angle X-ray diffraction (GAXRD) and X-ray photoelectron spectroscopy (XPS) techniques. The GAXRD analysis reveals Cu collector undergoes slight reconstruction of its (100) facets surface to (200) facets in the presence of the adhesion layer. Moreover, depth XPS analysis confirmed that the alignment of F atoms in the adhesion layer is toward the Cu collector which can play an important role for homogeneous Li deposition. Based on these findings, a novel approach is developed to prepare GPE, without peeling off the electrospun PVDF-HFP membrane from Cu collector to take advantage of the adhesion layer. The electrospun PVDF-HFP membrane GPE unpeeled off from its Cu collector (Cu@PVDF-HFP-10) prepared using novel method provides bifunctional applications, as electrolyte and as an artificial solid-electrolyte interphase (ASEI). The strong electrostatic interaction between the fiber sheet and its collector foil forms an adhesion layer (⁓0.5μm) which acts as ASEI prevents electrolyte decomposition. The Cu@PVDF-HFP-10|Li anode free cell enables uniform and highly compacted Li platting, excellent electrochemical performance, and high coulombic efficiency (CE) even at a high current density up to 5 mA cm− 2 (CE, 97.14%) after 200 cycles using 2 mAh cm− 2 capacity loading. Conversely, nonuniform and thick Li deposition is observed in the GPE prepared by conventional method (PVDF-HFP-10), due to poor contact between the membrane and the electrode, achieved only 90.08% CE after 100 cycles at 5 mA cm− 2. Post-cycling analyses using titration-gas chromatography (TGC) and XPS techniques indicated that the new strategy is conducive to prevent dead Li metal formation as well as to create a carbonate-free, robust, and stable SEI convenient to develop sustainable AFLMB system. Cycling performance of the Cu@PVDF-HFP-10 GPE utilized in the Cu|NMC AFLMB configuration delivered much better electrochemical performance than the PVDF-HFP-10 GPE (prepared by traditional method) and organic liquid electrolytes.

Multifunctional electrospun PVDF-HFP gel polymer electrolyte membrane suppresses dendrite growth in anode-free li metal battery

It is widely accepted that high electrolyte consumption due to decomposition leads to rapid capacity fading in anode-free Li metal batteries (AFLMBs). Here, we report an electrospun gel polymer electrolyte (GPE) membrane, unpeeled-off and integrated with its Cu foil collector (Cu@GPE), prepared using a novel method. The Cu@GPE provides bifunctional applications; as electrolytes and an artificial solid-electrolyte interphase (ASEI). Interestingly, the strong electrostatic interaction between the fiber sheet and the Cu foil collector reconstructs the Cu surface structure, confirmed by grazing angle X-ray diffraction, which positively influences the fluidity of deposited Li. X-ray absorption, depth profile of X-ray photoelectron, Raman and infrared spectroscopies analyses showed the formation of pure β-phase PVDF-HFP as ASEI in which the F elements are aligned toward the Cu surface. These lead to a uniform Li-ion flux and regulate the Li nucleation due to the strong binding between Li and electronegative C-F functional groups promoting uniform Li deposition. The Cu@GPE|Li cell achieved outstanding performance even at a high current density of up to 5 mA cm−2 (coulombic efficiency, 97.14%) after 200 cycles relative to the GPE prepared by the conventional method (cGPE) (90.08%) after 100 cycles. Coupling with LiNi0.33Mn0.33Co0.33O2 (NMC), the Cu@GPE|NMC AFLMB delivered superior performance than Cu|cGPE|NMC.

PICOSECOND PULSED LASER DEPOSITION OF MOS2 THIN FILMS

MoS2 thin films were grown by the pulsed laser deposition technique using a picosecond laser at a wavelength of 1030 nm. The plasma ion mean kinetic energy and density were estimated from the time-of-flight distributions measured using a Langmuir planar probe. It has been found that the mean kinetic energy decreases with increasing the laser pulse energy. This unusual effect is explained by the difference in the volatility of the vaporized species. Samples were structurally characterized by Raman spectroscopy and grazing angle X-ray diffraction. It was found that thin films of amorphous matrices containing MoS2 nanocrystallites were grown. Optical characterization carried out by UV-vis spectroscopy yielded transmittance values above 90% in the visible spectral range and an indirect electronic transition at 1.4 eV. Chemical oxidation states for molybdenum and sulfur were analyzed by means of X-ray photoelectron emission spectroscopy, which revealed Mo-S bonding states, confirming the growth of MoS2.

The effect of thickness on structural, optical, and electrical properties deposited ZnO thin films by PLD

In this paper, the effect of film thickness on structural, electrical, and optical properties of ZnO thin films deposited by Pulsed laser Deposition (PLD) over a quartz substrate has been studied. In PLD the thickness of the deposited thin films varies from 200 nm to 300 nm by increasing the number of laser shots from 9000 shots to 12,000 shots respectively. Deposited thin films were studied by Grazing angle X-ray diffraction (Gi-XRD), Ultraviolet–Visible transmittance spectroscopy (UV–Vis), Lateral I-V measurements, Field emission scanning electron spectroscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). Gi-XRD result shows that films deposited over quartz are poly-crystalline in nature and are oriented along (002), (102), and (103) planes. FESEM analysis shows that 300 nm thick film is distributed uniformly over the surface and 200 nm ZnO thin film is distributed mainly at the center. EDX results show the presence of Zn and O elements in both deposited thin films. I-V characteristics in the dark show Schottky contact with Vc 2.9 V and 1 V for 200 nm and 300 nm thin films respectively. The optical band gap of ZnO thin films intersects at the same photo energies for both thicknesses. Tauc’s plot of both films reveals the similar optical band gap energies of 3.25 eV in both deposited films.

Efficient Near-Infrared Luminescence of Self-Assembled Platinum(II) Complexes: From Fundamentals to Applications.

ConspectusDesigning bright and efficient near-infrared (NIR) emitters has drawn much attention due to numerous applications ranging from biological imaging, medical therapy, optical communication, and night-vision devices. However, polyatomic organic and organometallic molecules with energy gaps close to the deep red and NIR regime are subject to dominant nonradiative internal conversion (IC) processes, which drastically reduces the emission intensity and exciton diffusion length of organic materials and hence hampers the optoelectronic performances. To suppress nonradiative IC rates, we suggested two complementary approaches to solve the issues: exciton delocalization and molecular deuteration. First, exciton delocalization efficiently suppresses the molecular reorganization energy through partitioning to all aggregated molecules. According to the IC theory together with the effect of exciton delocalization, the simulated nonradiative rates with the energy gap ΔE = 104 cm-1 decrease by around 104 fold when the exciton delocalization length equals 5 (promoting vibronic frequency ωl = 1500 cm-1). Second, molecular deuterations reduce Franck-Condon vibrational overlaps and vibrational frequencies of promoting modes, which decreases IC rates by 1 order of magnitude in comparison to the rates of nondeuterated molecules under ΔE of 104 cm-1. Although deuteration of molecules has long been attempted to increase emission intensity, the results have been mixed. Here, we provide a robust derivation of the IC theory to demonstrate its validity, especially to emission in the NIR region.The concepts are experimentally verified by the strategic design and synthesis of a class of square-planar Pt(II) complexes, which form crystalline aggregates in vapor deposited thin films. The packing geometries are well characterized by the grazing angle X-ray diffraction (GIXD), showing domino-like packing arrangements with the short ππ separation of 3.4-3.7 Å. Upon photoexcitation, such closely packed assemblies exhibit intense NIR emission maximized in the 740-970 nm region through metal-metal-to-ligand charge transfer (MMLCT) transition with unprecedented photoluminescent quantum yield (PLQY) of 8-82%. To validate the existence of exciton delocalization, we applied time-resolved step-scan Fourier transform UV-vis spectroscopy to probe the exciton delocalization length of Pt(II) aggregates, which is 5-9 molecules (2.1-4.5 nm) assuming that excitons mainly delocalized along the direction of ππ stacking. According to the dependence of delocalization length vs simulated IC rates, we verify that the observed delocalization lengths contribute to the high NIR PLQY of the aggregated Pt(II) complexes. To probe the isotope effect, both partially and completely deuterated Pt(II) complexes were synthesized. For the case of the 970 nm Pt(II) emitter, the vapor deposited films of per-deuterated Pt(II) complexes exhibit the same emission peak as that of the nondeuterated one, whereas PLQY increases ∼50%. To put the fundamental studies into practice, organic light-emitting diodes (OLEDs) were fabricated with a variety of NIR Pt(II) complexes as the emitting layer, showing the outstanding external quantum efficiencies (EQEs) of 2-25% and the remarkable radiances 10-40 W sr-1 m-2 at 740-1002 nm. The prominent device performances not only successfully prove our designed concept but also reach a new milestone for highly efficient NIR OLED devices.This Account thus summarizes our approaches about how to boost the efficiency of the NIR emission of organic molecules from an in-depth fundamental basis, i.e., molecular design, photophysical characterization, and device fabrication. The concept of the exciton delocalization and molecular deuteration may also be applicable to a single molecular system to achieve efficient NIR radiance, which is worth further investigation in the future.

Comparative analysis of the biocompatibility of endothelial cells on surfaces treated by thermal plasma and cold atmospheric plasma.

In recent years, cold atmospheric plasma (CAP) is used for surface disinfection. However, little is known about its ability to improve biocompatibility of metallic surfaces when compared to thermal plasma methods. In this context, the study aimed to evaluate the response of human endothelial cells (Ea.hy926) on titanium surfaces treated by non-thermal plasma method and thermal plasma method under nitriding atmosphere. The wettability was characterized by the sessile drop method, the topography and roughness were evaluated by atomic force microscopy (AFM), and the microstructure by grazing angle X-ray diffraction (GIXRD). Endothelial cells were cultured and evaluated for morphology by scanning electron microscopy and viability by an MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. CAP treatment reduced the contact angle of the Ti surface (13.43° ± 1.48; p<0.05), increasing hydrophilicity. Rz roughness was higher on the nitrided surface (220.44±20.30; p< 0.001) compared to the CAP treated surfaces (83.29 ± 11.61; p< 0.001) and polished (75.98 ±34.21a); p<0.001). The different applied plasma treatments created different titanium surfaces improving the biocompatibility of endothelial cells, however CAP results demonstrate its potential for biomedical applications, considering the low cost and ease of use of the technique, allowing surface treatments before clinical procedures.

Plasma-enhanced atomic layer deposition of WO3-SiO2 films using a heteronuclear precursor

Tungsten oxide–silicon dioxide (WOx–SiOy) composite thin films were deposited for the first time via the remote oxygen plasma-enhanced atomic layer deposition (ALD) process using a novel metal-organic heteronuclear and heteroleptic precursor, bis(tert-butylimido)bis(trimethylsilylmethyl)tungsten. Self-limiting ALD growth was demonstrated over a wide temperature window of 203–328 °C with growth per cycle decreasing with increasing temperature from 0.75 to 0.4 Å/cycle, respectively. Residual gas analysis revealed ligand competition and showed that ligand reaction during ALD nucleation and growth was a function of deposition temperature, thereby affecting the film composition. As the temperature increased from 203 to 328 °C, the film composition [W/(Si + W)] ranged from 0.45 to 0.53. In addition, the carbon impurity content was reduced and the refractive index increased from 1.73 to 1.96, the density increased from 4.63 to 5.6 g/cm3, and the optical bandgap decreased from 3.45 to 3.27 eV. Grazing angle x-ray diffraction indicated that as-deposited films were amorphous. Upon annealing in O2 at 500 °C or higher, depending on deposition temperature, films are crystalized into the triclinic WO3 phase. At the same time, WO3 is sublimed from the surface and films are reduced in thickness.

Impact of thermally grown ZnS1-xOx buffer layer over the photovoltaic performance of SnS/ZnS heterostructure

Partial oxidation of high purity zinc sulfide thin films resulted in a thin layer of zinc oxysulfide over the zinc sulfide layer. The growth of the former at 450 °C was confirmed using grazing angle X-ray diffraction and small angle X-ray scattering. The zinc oxysulfide layer was employed as a buffer to improve the photovoltaic performance of SnS/ZnS based heterojunction by reduction of band offset. Inclusion of buffer layer between ZnS and SnS films was found to improve the photovoltaic performance compared to that of evaporated SnS/ZnS heterojunction.

Taguchi optimization of PEO process parameters for corrosion protection of AA7075 alloy

In this study, oxide coatings were grown by plasma electrolytic oxidation (PEO) process to enhance the corrosion resistance of the AA7075 alloys. The effect of process parameters on the corrosion resistance of PEO-treated AA7075 alloys was investigated systematically by the Taguchi analysis method the means of the three-level effects of four factors (current density, frequency, duty cycle, and electrolyte concentration). Grazing angle X-ray diffraction (GAXRD) has been used to determine phases on the surfaces. The surface morphology, thickness, pore diameter, and elemental analysis of the coatings were characterized with scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The corrosion behaviour of the PEO coatings was investigated using the potentiodynamic polarization scanning (PDS) technique in 3.5% NaCl solutions at room temperature. According to the signal-to-noise (S/N) ratio, optimum parameter/level combinations were determined for the best corrosion resistance. The percentage contribution of each parameter was determined by the analysis of variance (ANOVA). The results showed that frequency is the most significant parameter affecting the corrosion resistance of the PEO coatings. On the other hand, the highest polarization resistance of 2332 × 103 Ω cm2, 476 times better than the uncoated AA7075 substrate, was achieved in the confirmation run grown under optimum conditions.

ZnO Nanoneedle Based Efficient UV-Photodetector

This article reports the fabrication and characterization of nano-structured ITO/ZnO ultraviolet photodetector. A ZnO thin film was deposited by spray pyrolysis technique followed by interdigitated ITO as electrode deposition by RF sputter. Grazing angle x-ray diffraction (GIXRD) study indicates preferential growth along c-axis (002) of thin-film leading nanoneedle formation which was further confirmed by scanning electron microscopy (SEM) imaging. X-ray photoelectron spectroscopy (XPS) analysis of Oxygen 1s (O 1s) was carried out. A peak was observed at 531.8 eV indicating the presence of oxygen vacancy, 530 eV peak relates to the ZnO phase. The bandgap was determined by the Tauc plot; which was found to be 3.22eV. The donor carrier concentration is found to be 8.85x1018 cm-3 based on room temperature Hall measurement. A near ohmic behaviour was observed which can be interpreted by the existence of high carrier concentration in ZnO. This results in a very thin depletion width of the order of 5nm; therefore, charge transport through the junction is dominated by tunnelling of electrons through depletion width.

Effect of Ti content on preparation and properties of TiB&lt;sub&gt;2&lt;/sub&gt;-SiC-Ti materials

Since the 21st century, low atomic number material coating has been considered as one of methods for treating the first wall of controllable thermonuclear fusion device . The TiB&lt;sub&gt;2&lt;/sub&gt; material with high melting point, high hardness, low coefficient of thermal expansion, excellent wear resistance and low atomic number has entered into people’s field of vision. Single TiB&lt;sub&gt;2&lt;/sub&gt; is difficult to sinter and process into other products. Therefore, adding ceramic and metal additives to TiB&lt;sub&gt;2&lt;/sub&gt; matrix material to effectively improve the mechanical properties and processability of the material has become a research hotspot. On the basis of the existing researches of TiB&lt;sub&gt;2&lt;/sub&gt;-SiC, in the present work the metal Ti powder is added as the second additive to improve the properties of TiB&lt;sub&gt;2&lt;/sub&gt; composite. The TiB&lt;sub&gt;2&lt;/sub&gt; and SiC are mixed at a mass ratio of 2 to 3, then two kinds of TiB&lt;sub&gt;2&lt;/sub&gt;-SiC-Ti materials with different amounts of Ti content are prepared by spark plasma sintering (SPS) technology. The materials are irradiated by a He&lt;sup&gt;+&lt;/sup&gt; beam with energy of 60 keV and ion fluence of 2 × 10&lt;sup&gt;17&lt;/sup&gt; ions/cm&lt;sup&gt;2&lt;/sup&gt; at room temperature. The material is heat-treated at 1500 ℃ before and also after irradiation. The performances of prepared samples, the effect of irradiation on materials and the results of high temperature heat treatment are characterized by energy dispersive spectroscopy, Raman spectrum, grazing angle x-ray diffraction spectrum, Vickers hardness, wear resistance test, and scanning electron microscope. The results show that the surface morphology and toughness of TiB&lt;sub&gt;2&lt;/sub&gt;-SiC-Ti material with 3% Ti mass fraction are poor as shown in SEM images. The wear resistance test indicates that the material surface is seriously worn and the wear resistance is poor. The X-ray diffraction spectrum and Raman spectra show that the material is oxidized seriously at 1500 ℃, which is likely to be the cause of the poor compactness of materials. Raman spectra, Grazing angle X-ray diffraction spectrum and some Vickers hardness data before and after irradiation indicate that the material with low Ti content possess better crystal structure and weaker irradiation hardening. In conclusion, the TiB&lt;sub&gt;2&lt;/sub&gt;-SiC-Ti material with 3% Ti mass fraction exhibits lower density, poorer wear resistance and lower hardness, while the material with lower Ti mass fraction is more resistant to irradiation than the material with 6% Ti mass fraction at room temperature.

Atomic order-disorder engineering in the La2Zr2O7 pyrochlore under low energy ion irradiation

Cation and anion disordering affect the structural and electronic properties of the isometric A2B2O7 pyrochlore materials. Here, we report a study on the structural response of La2Zr2O7 at two different temperatures (300 K and ~88 K) as a function of ion fluence (1 × 1013, 5 × 1013, and 1 × 1014 ions/cm2). The effect of ion fluence and irradiation temperature on the structural properties have been investigated using the grazing angle x-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy. GIXRD results confirmed that the weakening/broadening of the diffraction peaks and lattice volume expansion increases monotonically as a function of ion fluence at both the temperatures and are more pronounced at ~88 K. The cation and anion disordering appear to be ion fluence and irradiation temperature-dependent. Raman spectroscopy shows that the atomic disordering is more pronounced with enhanced ion fluence and revealed the involvement of the X48f parameter in the enhancement of disordering in the system. The HRTEM analysis revealed that the deterioration in the atomic ordering (amorphization) is significantly more pronounced at ~88 K. The qualitative analysis of cation/anion disordering and structural deformation revealed that irradiation parameters play a crucial role in developing and altering the properties of the pyrochlore materials for the technological applications.