Glancing Incidence X-ray Diffraction Research Articles

Effect of the varied nitrogen vacancy concentration on mechanical and electrical properties of ZrNx thin films

ZrNx films were deposited with reactive magnetron sputtering in different [Ar]/([Ar] + [N2]) atmospheres and analyzed using X-ray photoelectron spectroscopy, glancing incidence X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, nanoindentation techniques, and four-point probe meter. N vacancy concentration is defined as VN = 1- x, where x is N/Zr ratio in ZrNx. Results showed that the VN ranged from 0.02, through 0.08, 0.13, 0.24 to 0.30. The glancing incidence X-ray diffraction results showed a decrease in lattice parameter a0 from 4.582, through 4.578, 4.571, 4.564 to 4.548 Å with the increase of VN from 0 to 0.30. Berkovich nanoindentation results showed that the hardness of ZrNx films increased from 18 ± 1.3 GPa to 24 ± 1.2 GPa with the increase of VN from 0 to 0.24, which is due to vacancy-induced hardening. However, further increase of VN to 0.30, a drop-in hardness was observed, which was attributed to vacancy-induced softening. Both hardening and softening proved the existing of a turning point at VN around 0.24. In addition, the fracture toughness and sheet resistance of ZrNx films also presented the same tendency. The experimental results agreed with first principle predictions that the metal-N (d-p) bonds, ZrZr (d-d) σ bonds and the valance electron density around Zr atoms had changed greatly due to the varied VN.

Impedance Spectroscopy of Vanadium Pentoxide Thin Films

V2O5 thin films have been deposited onto an insulating support by radiofrequency (rf) reactive sputtering from a metallic vanadium target at controlled flow rates of argon–oxygen gas mixture. Glancing-incidence x-ray diffraction (GIXD) analysis and scanning electron microscopy (SEM) were used for structural and phase characterization of the obtained materials. The as-sputtered thin films were found to consist of orthorhombic V2O5 phase. Electrical properties were determined by electrochemical impedance spectroscopy (EIS) conducted over the frequency range of 0.1 Hz to 1.4 MHz and temperatures ranging from room temperature (RT) to 773 K. Between RT and 528 K, the recorded impedance spectra were interpreted in terms of an equivalent circuit composed of a resistor and non-Debye constant-phase element (CPE) connected in parallel. In this temperature range, the material exhibited n-type extrinsic conductivity. The activation energy of electrical conductivity was 0.243 ± 0.023 eV. At 528 K, an abrupt change in resistivity was observed, interpreted as a metal–insulator transition (MIT). Above 528 K, the equivalent circuit was composed of a resistor (R) and inductor (L) connected in series, typical of materials exhibiting metallic properties.

Tetraallyltin precursor for plasma enhanced atomic layer deposition of tin oxide: Growth study and material characterization

In this letter, the authors report on the application of tetraallyltin (TASn) as an Sn-precursor for plasma enhanced atomic layer deposition (PEALD) of tin oxide (SnO2) thin films. The selection procedure for the TASn precursor is discussed. Tin oxide PEALD growth is shown to be self-limiting with a constant growth-per-cycle of 0.046 ± 0.002 nm/cycle in the substrate temperature (Tsub) range of 50–150 °C. Optical constants, chemical bonding, and electronic properties of as-grown PEALD films were characterized to evaluate the quality of tin oxide film obtained with the TASn precursor. A 21.6 nm tin oxide film grown at Tsub = 50 °C exhibited an indirect optical bandgap (Eg) of 2.94 eV and appeared amorphous from the glancing incidence x-ray diffraction pattern. Binding energy difference ΔBE(O1s, Sn3d5/2) = 43.77 eV and valence band emission in x-ray photoelectron spectroscopy showed that these were near-stoichiometric SnO2 with the relative O:Sn atomic ratio of 1.98 (or SnO1.98). Moreover, room temperature electrical resistivity ρele = 13.1 ± 1.6 mΩ cm, with electron concentration Ne = (3.78 ± 0.79) × 1019 cm−3 and Hall mobility μe = 13.2 ± 2.0 cm2 V−1 s−1, showed that electrical characteristics of the as-grown tin oxide films with the TASn precursor are comparable to those grown using other standard Sn precursors.

Structural and ferroelectric properties of Pr doped HfO2 thin films fabricated by chemical solution method

HfO2 thin films with different praseodymium doping contents (Pr:HfO2) were fabricated by chemical solution deposition (CSD) method at ambient conditions. The chemical bonding and the composition of Pr doped HfO2 thin film were characterized by X-ray photoelectron spectroscopy (XPS), while the structural properties were investigated by glancing incidence X-ray diffraction (GIXRD) and high resolution transmission electron microscopy (HRTEM). It is found that the ferroelectric orthorhombic phase was induced in the HfO2 based thin films by Pr doping. The combined results of P–E (polarization–electrical field) and C–V (capacitance–voltage) measurements demonstrated that the 5 mol% Pr doped HfO2 film exhibited a distinct ferroelectricity, with a maximum remanent polarization (Pr) of 6.9 µC/cm2 and a coercive field (Ec) of 1.2 MV/cm. Notably, the polarization did not show obvious degradation over 1 × 108 switching cycles, suggesting good endurance performance of the Pr doped HfO2 thin film. These results indicate that Pr dopant could effectively induce ferroelectricity in HfO2 thin films, thereby becoming a new member of dopants for HfO2 based ferroelectrics.

Physico-chemical studies of Cd1−xZnxS thin films produced by simple two-electrode electrodeposition system for solar cell application

Cd1−xZnxS thin films have been cathodically electrodeposited on glass/fluorine-doped tin oxide substrates using a low-cost two-electrode configuration with an electrolytic bath containing cadmium chloride, zinc chloride and sodium thiosulphate precursors. The deposition was carried out by varying zinc chloride concentration (0 M, 0.3 M, 0.6 M and 0.9 M) in the deposition electrolyte. The structural, compositional, phonon vibrational, morphological and optical properties of the resulting films have been characterized using glancing incidence X-ray diffraction, energy-dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and UV–Vis spectrophotometry respectively. The XRD result indicates the existence of hexagonal structure of Cd1−xZnxS with intensities of the diffraction peaks decreasing as more Zn is incorporated into the film as a result of decrease in deposition rate. EDX results show the presence of Cd, Zn and S in the deposited Cd1−xZnxS thin films. SEM images show uniform and densely packed surface morphology of the films with distinct shaped grains which gradually less distinct as more Zn is incorporated into the films. The optical measurements reveal a significant increase in energy band gap of the Cd1−xZnxS material as more zinc is incorporated into the films and a film thickness decreases with the energy band gap increasing from 2.40 eV for CdS to 2.62 eV for Cd1−xZnxS. These results show that Cd1−xZnxS material can be applied as a better window material for CdTe, CIG(S,Se) and CZTS-based solar cells than CdS.

Optical and Morphological Studies of Electrodeposited CdS Thin Film Grown at Different Deposition Times from Acetate Precursor

Electrodeposited cadmium sulfide (ED-CdS) thin films were prepared on fluorine-doped tin oxide (FTO) substrate at six different deposition times in order to study the impact of deposition time on their properties for possible solar cell application. The deposition was carried out from an electrolytic bath containing cadmium acetate Cd(CH3COO)2 and sodium thiosulfate (Na2S2O3) using simple two electrode configuration. The deposition time was varied at 30, 40, 50, 60, 70 and 80 minutes. The corresponding optical, morphological, surface roughness, compositional and structural properties of the deposited films were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM), scanning probe microscopy (SPM), energy dispersive X-ray spectroscopy (EDS) and glancing incidence X-ray diffraction (GIXRD) respectively. The results show that, the estimated energy band gaps were in the range of 2.35 to 2.20 eV as deposition time increases, for as-deposited films and 2.38 to 2.30 eV for annealed films. SEM images show very compact and agglomerated spherical grains. From SPM measurements it is observed that, the surface roughness ranges from 2.51 nm to 2.73 nm for as-deposited samples and 1.76 nm to 2.15 nm for annealed ones. EDS shows that the films are cadmium-rich in both as-deposited and annealed conditions.

Structural, vibrational, optical, morphological and compositional properties of CdS films prepared by a low-cost electrochemical technique

Very dense and uniform thin films of CdS were deposited on fluorine-doped tin oxide (FTO) substrates for thin film semiconductor devices application, such as in solar cells. The simplified electrochemical deposition method applied uses two-electrode system with FTO as the working electrode and high-purity graphite rod as the counter electrode. The CdS films grown at different cathodic voltages (1500 mV, 1550 mV and 1600 mV) were characterized for their structural, vibrational, optical, morphological and chemical compositional properties using state-of-the-art glancing incidence X-ray diffraction (GIXRD), Raman spectroscopy, UV–Visible spectrophotometry, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) respectively. XRD results reveal the existence of pure hexagonal crystal structure of CdS in the films in both as-grown and heat-treated conditions. The size of crystallites are in the range of (9–14) nm and (11–17) nm while the size of grains in these highly uniform and dense films are in the range (180–860) nm and (270–880) nm before and after annealing respectively. Raman results show the typical fingerprint of CdS in the form of the 1LO and 2LO phonon vibration peaks. The energy bandgaps obtained from optical measurements fall in the range of (2.50–2.59) eV which narrow down to 2.42 eV after annealing, for the different growth voltages used. EDX reveals all the films to be S-rich, with Cd/S ratio of ∼0.9 after annealing.

Effect of cadmium precursor on the physico-chemical properties of electrochemically-grown CdS thin films for optoelectronic devices application: a comparative study

Thin film CdS materials for possible optoelectronic devices application have been synthesized by the electrochemical deposition method, using two different cadmium salts and sodium thiosulphate as precursors. In order to keep the synthesis process as simple as possible, no additional chemicals were added as complexing agents or buffers, and a two-electrode set-up was used. The qualities of the resulting films from the different cadmium precursors were compared by characterizing them for their physico-chemical properties using state-of-the-art glancing incidence X-ray diffraction, UV–Vis spectrophotometry, scanning electron microscopy and energy dispersive X-ray spectroscopy (EDX). The results obtained show significant influence of cadmium precursor on the structural, optical and chemical properties of the films. Whereas CdCl2 precursor produced CdS with purely hexagonal structure in both as-grown and heat-treated conditions, Cd(CH3COO)2 produced CdS with purely cubic crystal structure, with films from both precursors showing clear difference in physical appearance. Energy bandgap values estimated for the films are in the range (2.49–2.57) eV and (2.22–2.23) eV in as-deposited form, with CdCl2 and Cd(CH3COO)2 precursors respectively. After annealing, these values become 2.42 eV with CdCl2 and (2.30–2.31) eV with Cd(CH3COO)2. Although CdS from both precursors show similar surface morphology, EDX results reveal that CdS films from CdCl2 precursor are more stoichiometric with Cd/S atomic ratios of (0.90–0.93) compared to films from Cd(CH3COO)2 precursor with Cd/S values of (0.87–0.88).

Study of vacancy defects and their thermal stability in MeV Fe ion irradiated RAFM steel using positron beam Doppler broadening spectroscopy

ABSTRACTIndian reduced activation ferritic-martensitic steel was irradiated with 1.1 MeV Fe ions to various doses from 1 to100 dpa at room temperature. The depth profiling of irradiation-induced vacancy-type defects and the defect-recovery under post-irradiation annealing was studied using variable low-energy positron beam Doppler broadening spectroscopy. The influence of irradiation-induced defects on the microstructural properties was studied by glancing incidence x-ray diffraction (GIXRD) and nanoindentation technique. Positron annihilation study showed the signatures of reduced vacancy concentration at the peak damage region due to injected interstitial effect from 30 to 100 dpa and the widening of vacancy-interstitial recombination-rich region towards the end of ion range with the increase in dose. The GIXRD results were analysed by modified Williamson–Hall plot method, and the variation of coherent domain size and micro-strain with irradiation dose was studied. Irradiation-induced hardening was observed in the nanoindentation study. The features observed in the GIXRD and nanoindentation study are correlated with the depth-resolved defect distribution observed in the positron annihilation study.

Study of the High Temperature Phase of 1,16-Hexadecanediol by Polarized Light Microscopy and Glancing Incidence X-Ray Diffraction

Study of the High Temperature Phase of 1,16-Hexadecanediol by Polarized Light Microscopy and Glancing Incidence X-Ray Diffraction

Electrochemical deposition and characterization of ZnOS thin films for photovoltaic and photocatalysis applications

Electrochemical deposition of zinc oxysulphide (ZnOS) thin films for possible photovoltaic and photocatalysis applications has been carried out using zinc acetate and sodium thiosulphate precursors in a simple two-electrode deposition set-up. The deposited films were characterized for their structural, optical, morphological and compositional properties using glancing incidence X-ray diffraction (GIXRD), UV–Vis spectrophotometry, scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy respectively. The detailed characterization results show that the ZnOS materials grown at different cathodic potentials of 1450 mV, 1500 mV and 1550 mV display desirable properties for the intended applications. Structural analysis shows that the films were formed by a combination of hexagonal ZnS and ZnO crystal phases. The energy bandgap estimated for the films across the explored potentials is in the range (2.68–3.26) eV for as-deposited films and (2.90–3.10) eV after annealing. These values and the transmittance were also shown to be increased significantly by reducing the deposition duration. SEM images show very compact and densely packed grains in the films while EDX results show Zn/S values of approximately unity and Zn/O values of approximately 0.1 across the deposition potentials explored, in both as-deposited and annealed conditions.

The material properties of novel boron doped InZnO thin films by solution process and its application in thin film transistors with enhanced thermal stability

Boron doped InZnO (BIZO) thin film has been fabricated via solution process and the effect of boron addition on the properties of BIZO thin film is investigated with the glancing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), the atomic force microscopy (AFM) and UV–vis spectrophotometer. The XPS spectra show that the oxygen vacancies in IZO semiconductor materials are effectively suppressed by boron contents due to high Lewis acid strength and strong bonding dissociation energy of BO. Moreover, the associated application in TFTs has also been fabricated by solution process and the thermal stability and electrical properties of solution processed BIZO-TFTs are investigated to confirm the decrease of oxygen vacancies in IZO materials. Meanwhile, the capacitance voltage measurement and the density of states are carried out to further investigate the enhanced electrical performance and thermal stability of TFTs due to the suppression of oxygen vacancies. Thus, the B doping is an effective method to suppress the generation of oxygen vacancies in IZO materials and to improve the thermal stability of solution processed BIZO-TFTs.

Phase Competition Induced Bio-Electrochemical Resistance and Bio-Compatibility Effect in Nanocrystalline Zrx-Cu100-x Thin Films.

Nano-crystalline Zrx-Cu100-x (x = 20-100 at.%) thin films with thickness ranging from 50 to 185 nm were deposited by magnetron co-sputtering with individual Zr and Cu targets. The as-sputtered thin films were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Atomic Force Microscopy (AFM) and Glancing Incidence X-ray Diffraction (GIXRD) for structural and morphological properties. The crystallite size was found to decrease from 57 nm to 37 nm upon increasing the Zr content from 20 to 30 at.% with slight increase in the lattice strain from 0.17 to 0.33%. Further, increase in Zr content to 40 at.% leads to increase in the crystallite size to 57 nm due to stabilization of C10Zr7 phase along with the presence of nanocrystalline Cu-Zr phase. A bimodal distribution of grain size was observed from FE-SEM micrograph was attributed to the highest surface roughness in Zr30Cu70 thin films comprised of Cu10Zr7, Cu9Zr2, Cu-Zr intermetallic phases. In-vitro electrochemical behaviors of nano-crystalline Zrx-Cu100-x thin films in simulated body fluid (SBF) were investigated using potentiodynamic polarization studies. Electrochemical impedance spectroscopy (EIS) data fitting by equivalent electrical circuit fit model suggests that inner bulk layer contributes to high bio-corrosion resistance in Zrx-Cu100-x thin films with increase in Zr content. The results of cyto-compatibility assay suggested that Zr-Cu thin film did not introduce cytotoxicity to osteoblast cells, indicating its suitability as a bio-coating for minimally invasive medical devices.

Depth Profiling of Strain in Textured Tungsten Films

ABSTRACTDevelopment of materials and engineering solutions in fusion technologies supports the use of high-Z elements as Plasma Facing Component to avoid tritium deposition with carbon. Tungsten is among the most promising candidates for these applications. Therefore, research in this area has gained increasing attention. It is then important to assess the structure and strain of thick W coatings as those parameters influence the adhesion on various substrates. This paper describes the status of investigations of strain in thick films of tungsten. Glancing incidence X-ray diffraction can be used to study W polycrystalline textured films, obtain information about their structure, and establish a depth profiling of residual strain. The actual strain at different depths within the coating can be extracted from the measured averaged strain using the inverse Laplace transform method applied to a set of measurements at different angles of the impinging X-ray beam. Results of measurements on films of different thicknesses are discussed.

Hydrogen storage studies in Pd/Ti/Mg films

This paper describes investigations (a) on the efficacy of Ti layer as a barrier against the intermixing of Pd and Mg in Pd/Ti/Mg films and (b) the hydrogen storage characteristics of the tri-layered films and the related bulk composites. The Mg film was prepared by resistive evaporation while the Pd and Ti films were deposited by e-beam evaporation. The analysis by Rutherford backscattering spectrometry (RBS) and glancing-incidence X-ray diffraction (GI-XRD) of the Pd/Ti/Mg/Si(substrate) films annealed in vacuum in 348–573 K temperature range revealed that Ti effectively prevents the intermixing of Pd and Mg up to ∼523 K. However, mixing across Pd/Ti, Ti/Mg and Mg/Si interfaces commences around 523 K that progresses with the temperature of annealing though PdMg phases are not formed even at 573 K. The as-deposited Pd/Ti/Mg films are hydrogenated to ∼7 wt % (62 at%) at 323–423 K at 0.15 MPa hydrogen pressure and dehydrogenated completely at ∼ 473 K. The extent of (de)hydrogenation of the films was determined non-destructively by the 1H(19F,αγ)16O nuclear reaction. The powder composites derived from the films, on the other hand, reversibly stored ∼2.2 wt% hydrogen up to 18 cycles in 323–473 K temperature range. The superior cyclic stability is attributed to the inhibition of mixing between Pd and Mg and, as a result, the formation of PdMg inter-metallics by titanium.

Effect of annealing treatment on sputtered copper oxide thin film

Copper oxide thin films were prepared on silicon wafer and glass slide substrate by dc reactive magnetron sputtering using a copper target without substrate heating. As-deposited CuO thin films were then annealed at various the temperatures in air ambient. The effects of annealing treatment on the physical morphology, optical property of the prepared samples were studied by glancing incident X-ray diffraction (GIXRD), field-emission scanning electron microscopy (FE-SEM), UV-Vis-NIR spectrophotometer. The results shown that the crystallinity of the CuO thin films was significantly improved as an annealing temperature increased. Additionally, the sheet resistance measurements were characterized on as-deposited and annealed samples in order to discuss the electrical properties.

Cosputtered Calcium Manganese Oxide Electrodes for Water Oxidation.

Calcium manganese oxide films were prepared by cosputter deposition from Mn and CaMnO3 targets and evaluated for their suitability as catalysts for the oxygen evolution reaction (OER). Scanning electron microscopy (SEM) revealed a compact morphology for the as-deposited films and the formation of nanorodlike features on the surfaces after annealing at 600 °C. X-ray-photoelectron-spectroscopy analysis showed that the surface oxidation state is close to +III (as in Mn2O3) for the as-deposited films and increases slightly to a mixture of III and IV after annealing occurs in dry air at 400-600 °C. Glancing-incidence X-ray diffraction (GIXRD) suggested that the CaMnxOy films are amorphous even when heated to 600 °C. However, transmission electron microscopy (TEM) showed that there is actually a polycrystalline component of the film, which best matches Mn3O4 (hausmannite with the average Mn oxidation state of ∼+2.7) but may have a slightly expanded unit cell because of the incorporation of Ca. Electrochemical analyses revealed that the as-deposited CaMnxOy films were OER-inactive. In contrast, annealing at 400 or 600 °C resulted in an increase of ∼15-fold in the current densities, which reached j ≅ 1.5 mA·cm-2 at OER overpotentials of η ≈ 550 mV in cyclic voltammetry (CV) sweeps. For the same η, annealed CaMnxOy electrodes also showed good electrochemical stabilities during 2 h of electrolysis, as rather constant steady-state current densities of j ≅ 0.4-0.5 mA·cm-2 were observed. The thicknesses and surface morphologies of the CaMnxOy films did not change during the electrochemical measurements, indicating that corrosion was negligible. In comparison with a previous study in which Ca-free thin layers of MnOx were evaluated, the results demonstrate that Ca2+ incorporation can enhance the OER activity of MnOx electrocatalysts prepared by sputter deposition. This work provides guidance for designing new electrodes for water oxidation on the basis of the abundant and nontoxic elements manganese and calcium.

Corrosion of Nickel Alloys in Molten LiCl-KCl Medium Under Cl2 Bubbling

Pyrochemical reprocessing utilizing molten chloride salt medium has been considered as one of the best options for the reprocessing of spent metallic fuels from future fast breeder reactors. Purification of molten salt is an important step where chlorine gas is purged in molten LiCl-KCl eutectic salt at 873 K. Materials for manufacturing of vessels and components for salt purification system should possess high corrosion resistance under such a highly corrosive environment. The present paper discusses the corrosion behavior of INCONEL Alloys 600 (UNS N06600), 625 (UNS N06625), and 690 (UNS N06690) and their welds in molten LiCl-KCl eutectic salt at 873 K under Cl2 bubbling. Characterization of the exposed surfaces was performed by using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy, and glancing incidence x-ray diffraction. The results of the present study indicated that N06600 and N06690 offered better corrosion resistance compared to N06625. Surface morphology of the exposed base metal and weld metal surfaces exhibited intergranular and interdendritic corrosion, respectively, on N06600 and N06625. SEM micrographs clearly indicated that N06690 exhibited uniform dissolution, while N06600 and N06625 exhibited localized attack. The paper highlights the results of the present investigation.

Microstructure analysis of silicon nanocrystals formed from silicon rich oxide with high excess silicon: Annealing and doping effects

Thin films consisting of silicon nanocrystals fabricated by high silicon content in silicon rich oxide show unique properties of decreasing resistivity and increasing light absorption while maintaining quantum confinement effects. With that said, the effect of the annealing temperature and doping element on the microscopic structure of silicon nanocrystals (Si NCs) and the film are still under research. In this study, individual intrinsic, boron-, and phosphorus-doped films are annealed at various temperatures, and their structural properties are analyzed via atom probe tomography together with glancing incidence x-ray diffraction, Raman spectroscopy (Raman), transmission electron microscopy (TEM), and energy filtered TEM. In addition, photoluminescence (PL) is performed and linked with their microstructural properties. The Si NC growth is confirmed at annealing temperatures of 1000 °C and 1100 °C. The microstructure of the Si NCs in the whole film is dramatically changed by increasing the annealing temperature from 1000 °C to 1100 °C. In addition, doping changes the arrangement of the Si NCs by assisting their penetration across the SiO2 barrier layers. This study helps to understand the relationship between the microscopic and macroscopic properties of the Si NC film, showing that the size and distribution of the Si NCs are correlated with the obtained PL profiles.

Optoelectronic effect of porous silicon surface treatment with samarium ions for different deposition times and characterizations

The goal of the present investigation is to reduce the stress, strain, and defects of porous silicon through a passivation process. We have investigated different layers of porous silicon (PSL) which were intentionally doped with samarium (Sm) by the electrochemical deposition. The used precursors were samarium oxides (Sm2O3) 0.05 M mixed with sulfuric acid (H2SO4) 0.05 M. The influence of samarium on the distribution of oxygen was studied by Fourier transform infrared spectroscopy (FTIR). Indeed, the glancing incidence X-ray diffraction proves the degree of structural order in PS and the presence of these complex metals (Sm) on its surface. The dispersion of the Sm metals on the PS surface (Sm/PSLs) exhibited better performances for the treated wafers in regard to the untreated ones. That means, we obtained a noteworthy increase in the effective minority carrier lifetime τ eff and an apparent enhancement in photoluminescence (PL) intensity. Particularly, the chief goal of the current study is to clarify that the large enhancement of the electronic quality of the wafers is related to the presence of Sm.