Grazing Incidence X-ray Diffractometry Research Articles

Ternary Polymer Solar Cells: Impact of Non-Fullerene Acceptors on Optical and Morphological Properties

Ternary organic solar cells contain a single three-component photoactive layer with a wide absorption window, achieved without the need for multiple stacking. However, adding a third component into a well-known binary blend can influence the energetics, optical window, charge carrier transport, crystalline order and conversion efficiency. In the form of binary blends, the low-bandgap regioregular polymer donor poly(3-hexylthiophene-2,5-diyl), known as P3HT, is combined with the acceptor PC61BM, an inexpensive fullerene derivative. Two different non-fullerene acceptors (ITIC and eh-IDTBR) are added to this binary blend to form ternary blends. A systematic comparison between binary and ternary systems was carried out as a function of the thermal annealing temperature of organic layers (100 °C and 140 °C). The power conversion efficiency (PCE) is improved due to increased fill factor (FF) and open-circuit voltage (Voc) for thermal-annealed ternary blends at 140 °C. The transport properties of electrons and holes were investigated in binary and ternary blends following a Space-Charge-Limited Current (SCLC) protocol. A favorable balanced hole–electron mobility is obtained through the incorporation of either ITIC or eh-IDTBR. The charge transport behavior is correlated with the bulk heterojunction (BHJ) morphology deduced from atomic force microscopy (AFM), contact water angle (CWA) measurement and 2D grazing-incidence X-ray diffractometry (2D-GIXRD).

Superconductivity of amorphous and crystalline Re–Lu films

We report on superconducting properties of a novel material: rhenium-lutetium films. Different compositions of Re x Lu binary are explored from x ≈ 3.8 to close to pure Re stoichiometry. The highest critical temperature, up to Tc≈ 7 K, is obtained for x ≈ 10.5 in accordance with electron dispersive spectroscopy results. Depending on the deposition conditions, polycrystalline or amorphous films are obtainable, both of which are interesting for practical use. Crystalline structure of polycrystalline phase is identified as a non-centrosymmetric superconductor using grazing incidence x-ray diffractometry. Superconducting properties were characterized both resistively and magnetically. Magnetoresistivity and AC/DC susceptibility measurements allowed us to determine Hc1 and Hc2 of these films, as well as estimate coherence length ξ(0) and magnetic penetration depth λL(0) . We also provide information on surface morphology of these films. Demonstration of superconductivity in this material justifies the point of view that Lu plays a role of group 3 transition metal in period 6 of the Periodic table of elements. Then, in analogy with Re–Nb, Re–Ti, Re–Hf and Re–Zr, one can expect that crystalline Re–Lu also breaks time-reversal symmetry. If that is proven by future experiments, in combination with noncentrosymmetric feature, these films could be used for forming nonreciprocal current devices, such as superconducting diodes, without involvement of external magnetic fields.

Optical, structural and mechanical properties of TiO2 and TiO2-ZrO2 thin films deposited on glass using magnetron sputtering

In this study, the structural, optical, and mechanical properties of magnetron sputtered TiO2 and TiO2-ZrO2 mixture transparent thin films along with the effect of heat treatment were investigated. TiO2 and TiO2-ZrO2 thin films were fabricated by magnetron sputtering from ceramic targets at room temperature on both the soda-lime and the borosilicate glass substrates. Structural properties of thin films were studied via X-ray photoelectron spectroscopy (XPS), grazing incidence X-ray diffractometry (GI-XRD) and scanning electron microscopy (SEM). Optical characterizations were carried out using spectrophotometry and spectroscopic ellipsometry. The hardness and scratch behavior of the samples were investigated using nano-indentation and nano-scratch tests. TiO2 and ZrO2 presence in films was confirmed by XRD and XPS analysis. It was found that TiO2-ZrO2 films show higher hardness values compared to TiO2 thin films. It was also seen that ZrO2 presence in TiO2-ZrO2 thin films prevents the crystallization of TiO2 after annealing compared to TiO2 thin films that resulted in better surface quality and higher thermal stability after annealing. The addition of ZrO2 to TiO2 resulted also in the shifting of the absorption edge to smaller wavelengths while decreasing the sharpness thus providing less absorption in the visible area, especially in the range of 380–500 nm. The refractive index of TiO2-ZrO2 thin film remained relatively unchanged compared to TiO2 after annealing, making it more preferable in terms of optical stability.

Structure and phase composition study of thin TiO2:C films deposited by r.f. magnetron sputtering

Thin films of TiO2 doped with carbon were deposited on 15×25×1 mm3 glass substrates by r.f. magnetron co-sputtering of TiO2 target and carbon plates on their erosion zone in Ar + air atmosphere (0.5 Pa and 0.6 Pa, respectively). Two different process parameters were varied in different experiments: the total area of the carbon plates (84 mm2, 560 mm2, 830 mm2 or 1480 mm2) and the radial distance from the center of the circle of the erosion zone with maximum rate of sputtering (2 cm or 4 cm). The as-deposited and annealed (air, 400 °C, 1 h) thin films with thicknesses of 40 - 60 nm were studied by ellipsometry, grazing incidence X-ray diffractometry (GIXRD), Raman spectroscopy, transmission (TEM) and scanning electron microscopies (SEM). The ellipsometric studies revealed the band gap, as well as the tail states and optical constants of the thin films obtained. The GIXRD patterns revealed a mix of amorphous and nanocrystalline anatase and rutile TiO2 phases in all thin films. The Raman study confirmed this conclusion, but the TEM study showed the presence of some nanocrystalline C20O14Ti3, together with the other TiO2 phases - brookite and nonstoichiometric TiOx phases (anatase and rutile). The effects of annealing at 400 °C in air for 60 min are also discussed.

Применение метода GIXRD для исследования нарушенных слоев в керамиках NaNd(WO_4)-=SUB=-2-=/SUB=- и NaNd(MoO_4)-=SUB=-2-=/SUB=-, подвергнутых облучению высокоэнергетическими ионами

The technique of grazing incidence X-ray diffractometry (GIXRD) was used to study damaged layers in NaNd(WO4)2 and NaNd(MoO4)2 ceramics irradiated with high-energy ions. The possibilities and applicability limits of the technique for the analysis of such samples are shown. Estimates of the degree of amorphization in near-surface layers of ceramics are given depending on the irradiation dose. The higher resistance of NaNd(MoO4)2 ceramics to external radiation exposure as compared to NaNd(WO4)2 has been demonstrated.

Application of the GIXRD Technique to Investigation of Damaged Layers in NaNd(WO_4)-=SUB=-2-=/SUB=- and NaNd(MoO_4)-=SUB=-2-=/SUB=- Ceramics Irradiated with High-Energy Ions

The technique of grazing incidence X-ray diffractometry (GIXRD) was used to study damaged layers in NaNd(WO_4)2 and NaNd(MoO_4)2 ceramics irradiated with high-energy ions. The possibilities and applicability limits of the technique for the analysis of such samples are shown. Estimates of the degree of amorphization in near-surface layers of ceramics are given depending on the irradiation dose. The higher resistance of NaNd(MoO_4)2 ceramics to external radiation exposure as compared to NaNd(WO_4)2 has been demonstrated. Keywords: X-ray diffraction, Parallel beam method, Grazing incidence geometry, Ion irradiation, Ceramics, Radiation resistance, Amorphization, Damaged layer.

Synthesis of graphene–like phases by laser ablation of micro-crystalline graphite in water suspension

The aim of our work was to obtain graphene-like phases (defected graphene, graphene oxide and reduced graphene oxide) as fine suspensions by applying pulsed laser ablation (PLA) to microcrystalline graphite suspension in water medium. The fundamental (λ = 1064 nm), second (λ = 532 nm), third (λ = 355 nm) as well as the fourth harmonic (λ = 266 nm) of a Nd:YAG laser system, 15 ns pulse duration and 10 Hz pulse repetition rate were used in PLA processes. The morphology of the particles was studied by transmission electron microscopy (TEM). Their phase composition and structure were explored by Raman and X-ray Photoelectron spectroscopies, grazing incidence X-ray diffractometry (GIXRD) and high temperature powder X-ray diffraction (HTXRD) and TEM. It can be assumed, in accordance to the XPS, TEM and Raman studies, that the colloids obtained by all experiments contain predominantly rGO and defected graphene, but also some GO, graphite micro-particles, and graphene-like phases. Amorphous carbon is frequently observed in by PLA at λ = 355 nm as well as at λ = 266 nm at high laser beam fluences but it can be found in very small quantities in all specimens. The XPS analysis of the samples revealed a significant increment in the quantity of different oxygen–containing radicals as a function of the fluence, which is a result of the quantity of the sp3–hybridized carbon. Finally, the established PLA procedures have been found to be highly reproducible.

Applying surface-sensitive techniques to structural and chemical study of uncapped Sn-Sb-Te thin film. A density functional theory - based study

We present here a combined experimental and theoretical study of the structural and chemical properties of polycrystalline Sn-Sb-Te film with nominal composition SnSb2Te4 grown by pulsed laser deposition technique on mylar substrate. From the experimental side, surface-sensitive techniques as x-ray photoelectron spectroscopy (XPS), grazing incidence x-ray diffractometry (GIXRD) and 119mSn integral conversion electron Möβbauer spectroscopy (ICEMS) have been applied to the study of the film at room-temperature and under normal conditions of pressure. GIXRD showed that the Sn-Sb-Te film adopted a NaCl- type structure (Fm-3m), and in the detection limits, no other crystalline phase was revealed. ICEMS technique unambiguously indicated the coexistence of two different tin fractions: Sn(II), as expected for the SnSb2Te4 phase, and Sn(IV), suggesting oxidation of tin. Chemical in-depth profile obtained by means of XPS suggests the oxidation of all the constituent atoms at the topmost layers of the film and the progressive depletion of tin and antimony oxides going depth in the film. The in-depth atomic concentration profiles also reveals a notorious deficiency of Te in the sample. Theoretically, density functional theory-based calculations (assuming that the Sn-Sb-Te film adopts the Fm-3m structure) support the hypothesis that Te - vacancies sites are occupied by oxygen atoms during the natural oxidation process of Sn-Sb-Te film. Additionally, our calculations demonstrated that only the substitution of Te atoms by oxygen ones induces a semiconducting behavior of the otherwise metallic Sn-Sb-Te host.

Direct liquid injection chemical vapor deposition of ZrO2 films from a heteroleptic Zr precursor: interplay between film characteristics and corrosion protection of stainless steel

The direct liquid injection chemical vapor deposition (DLI-CVD) of uniform and dense zirconium oxide (ZrO2) thin films applicable as corrosion protection coatings (CPCs) is reported. We present the entire development chain from the rational choice and thermal evaluation of the suitable heteroleptic precursor [Zr(OiPr)2(tbaoac)2] over the detailed DLI-CVD process design and finally benchmarking the CPC behavior using electrochemical impedance spectroscopy (EIS). For a thorough development of the growth process, the deposition temperature (Tdep) is varied in the range of 400 – 700 °C on Si(100) and stainless steel (AISI 304) substrates. Resulting thin films are thoroughly analyzed in terms of structure, composition, and morphology. Grazing incidence X-ray diffractometry (GIXRD) reveals an onset of crystallization at Tdep ≥ 500 °C yielding monoclinic and even cubic phase at low temperatures. At Tdep = 400 °C, isotropic growth of XRD amorphous material is shown to feature cubic crystalline domains at the interfacial region as revealed by electron diffraction. Corrosion results obtained through EIS measurements and further immersion tests revealed improved CPC characteristic for the 400 °C processed ZrO2 coatings compared to the ones deposited at Tdep ≥ 500 °C, yielding valuable insights into the correlation between growth parameter and CPC performance which are of high relevance for future exploration of CPCs.

Nd:YAG laser ablation of micro-crystalline graphite in a water suspension

The aim of this work was to obtain graphene-like phases (defected graphene, graphene oxide and reduced graphene oxide) as fine suspensions by applying pulsed laser ablation (PLA) of micro-crystalline graphite suspension in water medium. The fundamental (λ = 1064 nm), second (λ = 532 nm), third (λ = 355 nm) and fourth harmonics (λ = 266 nm) of a Nd:YAG laser system (15-ns pulse duration and 10-Hz pulse repetition rate) were used. The morphology of the particles was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Their phase composition and structure were explored by Raman and X-ray photoelectron spectroscopies, grazing incidence X-ray diffractometry (GIXRD) and TEM. The specimens were prepared by drop-casting on a glass substrate (for Raman and GIXRD studies) and on a standard TEM copper mesh for SEM and TEM examination.

RF magnetron sputtering of Bi12TiO20 thin films on various substrates

Using RF magnetron sputtering, we deposited Bi12TiO20 (BTO) thin films on various substrates (glass, quartz, stainless steel (SS304), (001) and (111) Si and sital-ceramics, Al and Cu foils). The films had a constant thickness of 1.3 μm. The as-deposited films were studied by Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), as well as by grazing incidence X-ray diffractometry (GIXRD). The GIXRD results reveal that the films are amorphous, while the Bi/Ti ratio varies between 9.5/1 and 11.8/1, as shown by the energy dispersive X-ray analysis (EDX). Further, the films deposited on glass and SS304 substrates were modified by laser irradiation (CuBr laser with a wavelength λ = 511 nm) to obtain an ordered cubic phase. The films deposited on quartz and on (001) and (111) Si substrates were thermally annealed at about 510 oC for three hours in ambient atmosphere. The modified films were characterized by Raman spectroscopy, scanning electron microscopy (SEM), EDX and X-ray diffractometry.

Ordered arrangement of F4TCNQ anions in three-dimensionally oriented P3HT thin films

An ordered arrangement of electron-accepting molecular dopant, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), in three-dimensionally (3D) oriented poly(3-hexylthiophene) (P3HT) film was clarified. The 3D oriented P3HT thin films prepared by the friction-transfer technique were doped with F4TCNQ by dipping into an acetonitrile solution. The presence of F4TCNQ anions in the 3D oriented P3HT thin films was investigated by polarized ultraviolet/visible/near-infrared absorption spectroscopy, grazing incidence X-ray diffractometry, polarized Fourier transform infrared spectroscopy (FT-IR), and infrared p-polarized multiple-angle incidence resolution spectroscopy (pMAIRS). The F4TCNQ-doped 3D oriented P3HT films showed anisotropic properties in all characterizations. In particular, the anisotropic molecular vibrations from polarized FT-IR and pMAIRS have clearly revealed orientations of polymeric chains and molecular dopant molecules. Considering the results from several independent techniques indicated that F4TCNQ anions in the 3D oriented P3HT were orderly arranged in a 3D manner with respect to the 3D oriented P3HT such that their molecular long-axis parallel to the P3HT backbone, with in-plane molecular orientation. Additionally, the direction of the optical transition moment of the F4TCNQ anion was found to be parallel to the molecular short-axis.

固／水界面における毛髪コンディショナー吸着膜の構造解析のための 微小角入射X線回折測定システムの開発

固／水界面における毛髪コンディショナー吸着膜の構造解析のための 微小角入射X線回折測定システムの開発

Sodium chloride assists copper release, enhances antibacterial efficiency, and introduces atmospheric corrosion on copper surface

Sodium chloride (NaCl) is commonly found in physiological buffers. This study found out its additional but important role in antibacterial efficiency test by better corroding metallic copper surface. Combined with multiple characterisation methods including scanning electron microscopy, grazing incidence X-ray diffractometry, and inductively coupled plasma mass spectrometry, 0.9% saline was observed to cause localised corrosion attacks on copper surface, enhancing release of copper content. The 1 h killing rate against Escherichia coli was thus promoted from 22% (when re-suspended in pure water) to 98%. By a long-term observation (3-week), residual NaCl crystals on 0.9% saline treated copper surface were found partially disappeared in atmospheric environment, contributing to an additional Cu2O layer forming above the treated surface. Besides, formation of oxygen-containing species was observed on fresh copper surface exposed by focused ion beam after saline treatment, suggesting a chloride-assisted atmospheric corrosion process.

The passivity of low-temperature carburized austenitic stainless steel AISI-316L in a simulated boiling-water-reactor environment

The passive film on low-temperature-carburized AISI-316L austenitic stainless steel was studied in an oxygenated, simulated boiling-water-reactor environment with normal water chemistry. The microstructure was studied using scanning electron microscopy, grazing-incidence X-ray diffractometry, Auger electron spectroscopy, X-ray energy-dispersive spectroscopy, and transmission electron microscopy. For non-surface engineered AISI-316L, three distinct layers were observed after exposure: an outer layer of larger nickel-oxide enriched particles with the spinel structure, an intermediate layer of small Cr-oxide-enriched hematite particles, and a compact inner layer of Cr-enriched oxide also having the spinel structure. Exposure of low-temperature-carburized AISI-316L, in contrast, resulted in only two distinct layers. These layers did not include a compact Cr-rich inner layer. Instead, the innermost layer consisted of an oxide with the spinel structure that was a mixture of Fe, Cr and Ni oxide. The outer layer on the low-temperature-carburized specimen consisted of large loosely stacked particles with the spinel structure of mixed composition. In addition to passive-film characterization, the corrosion rate was studied by monitoring mass loss. After 500 h of immersion, the mass changes measured were relatively low for all specimens indicating good adhesion and low oxidation rates.

Crystallization behavior of amorphous BaTiO3 thin films

The crystallization behavior of amorphous barium titanate (BaTiO3) thin films was studied as a function of annealing temperature from 500 to 1000 °C. Quantitative phase analysis by grazing incidence X-ray diffractometry revealed that the metastable hexagonal phase preferentially nucleates at lower temperatures with a transition to stable cubic nuclei at higher temperatures. The predominance of the metastable hexagonal-phase nucleation at lower temperatures suggests that it has the lowest nucleation barrier, in accordance with the Ostwald’s step rule. To help induce the nucleation of the cubic phase at lower temperatures, we explored the effects of electric fields on the crystallization behavior and found that direct-current fields moderately enhanced the cubic phase fraction in the 500–700 °C temperature range. Although the nucleation barrier of the cubic phase in the presence of an electric should be lowered more significantly with respect to that of the hexagonal phase because of the former’s higher relative permittivity, the effect arising from the change in volume free energy should only become significant at electric field strengths in the range of MV cm−1, an order of magnitude higher than the experimentally accessible fields in the present study. This suggests alternative, perhaps interface-mediated, mechanisms by which the electric field modifies the nucleation behavior of BaTiO3.

Structural and optical properties of thin TiO2:C films – influence of the substrate-erosion zone radial distance

The structural and optical properties were studied of thin TiO2:C films deposited on glass substrates by r.f. magnetron co-sputtering of a TiO2 target and carbon plates placed on its erosion zone in an atmosphere of Ar (0.5 Pa) + air(0.6 Pa). The total area of the carbon plates was 830 mm2, and the radial distance between the center of the glass substrates (15×25×1 mm) and the circle of the erosion zone with a maximum sputtering rate was 2 cm and 4 cm. The as-deposited and annealed (air, 400 °C, 1 h) thin films with a thickness of about 150 nm were studied via reflectance and transmittance measurements, X-ray photoelectron spectroscopy (XPS), grazing incidence X-ray diffractometry (GI XRD) and Raman spectroscopy. The optical spectra of the thin films deposited at the higher radial distance from the erosion zone maximum demonstrated absorption in the visible range. The XRD patterns revealed a mix of amorphous and nano-crystalline anatase and rutile TiO2 phases in all thin films. The reflections of the experimental XRD patterns indicated the presence of tensile stress in the grains. The Raman spectra confirmed the nano-crystalline structure of the anatase and rutile phases of the films. The incorporation is discussed of C atoms in the TiO2 films.

Electrochemical Surface Oxidation of Copper Studied by in Situ Grazing Incidence X-ray Diffraction

Grazing incidence X-ray diffractometry (GIXRD) can deliver integral information on the structure and chemistry of surface near regions, which can be beneficial for functional materials related to i...

Atomic Layer Deposited TiO₂ and Al₂O₃ Thin Films as Coatings for Aluminum Food Packaging Application.

Titanium dioxide (TiO2) and aluminum oxide (Al2O3) coatings have been investigated in a wide range of bio-applications due to their biodegradation and biocompatibility properties, that are key parameters for their use in the food packaging and biomedical devices fields. The present study evaluates and compares the electrochemical behavior of the non-coated, commercial resin-coated, TiO2-coated and Al2O3-coated aluminum in commercial beer electrolyte. For this, TiO2 and Al2O3 thin films were deposited on aluminum (Al) substrates using atomic layer deposition (ALD). The evaluation of the corrosion barrier layer properties was performed by linear sweep voltammetry (LSV) during 10 min and electrochemical impedance spectroscopy (EIS). In addition, profilometry, grazing incidence X-ray diffractometry (GIXRD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR) analyses were performed to investigate the physical and chemical properties of the pristine and / or corroded samples. TiO2 and Al2O3 films presented an amorphous structure, a morphology that follows Al substrate surface, and a thickness of around 100 nm. Analysis of LSV data showed that ALD coatings promoted a considerable increase in corrosion barrier efficiency being 86.3% for TiO2-coated Al and 80% for Al2O3-coated Al in comparison with 7.1% of commercial resin-coated Al. This is mainly due to the lower electrochemical porosity, 11.4% for TiO2-coated Al and 20.4% for Al2O3-coated Al in comparison with 96% of the resin-coated Al, i.e. an increase of up to twofold in the protection of Al when coated with TiO2 compared to Al2O3. The EIS results allow us to complement the discussions about the reduced corrosion barrier efficiency of the Al2O3 film for beer electrolyte once SEM and FT-IR analyzes did not show drastic changes in both investigated ALD films after the corrosion assays. The above results indicate that ALD TiO2 and Al2O3 films may be a viable alternative to replace the synthetic resin coatings frequently used in aluminum cans of use in the food industry.

High figure of merit p-type transparent conducting thin film based on solution processed CuS-ZnS nanocomposite

Until now only n-type transparent conducting films (TCFs) have accomplished sufficient maturity while p-type TCFs are still in infancy which limits the success of all-transparent electronics. Considerable endeavors are made till date for development of new p-type TCFs with limited success. Here, we report a highly transparent and conducting p-type thin films (∼60 nm) based on CuS-ZnS nanocomposite deposited by simple chemical bath deposition method at ∼80 °C on glass substrates using different x values (0.1, 0.35, 0.6, 0.8) where x = Cu (mol %)/(Cu+Zn) (mol%). Grazing incidence X-ray diffractometry, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and atomic force microscopy are used to evaluate the structural and microstructural characteristics of the films. The existence of ZnS phase is seen only for x ≤ 0.6 due to a preferential deposition of CuS which helps to retain a significant visible light transparency for x = 0.6 with a small drop in the conductivity value as compared to CuS. Thus the film with x = 0.6 is found to have the optimum electrical properties with resistivity, hole concentration, and mobility values of 1.03×10−3 Ω-cm, 4.16 × 1022 cm−3, and 0.15 cm2/Vs respectively as well as an optical transmission value of 83% at 550 nm. An unprecedented figure of merit value of 9.2 × 10−4 Ω−1 is obtained for the optimized film which is not reported till date to our knowledge. A p-n heterojunction is fabricated using the optimized film on n-GaN which shows a rectification ratio of 3.06 × 104 at 2 V indicating a great potential as p-type TCF for flexible transparent electronics.