Energy Dispersive Analysis By X-rays Research Articles

Synthesis of Aluminium Nanoparticles in A Water/Polyethylene Glycol Mixed Solvent using μ-EDM

Nanoparticles present a practical way of retaining the results of the property at the atomic or molecular level. Due to the recent use of nanoparticles in scientific, industrial and medical applications, synthesis of nanoparticles and their characterization have become considerably important. Currently, aluminium nanoparticles have attracted significant research attention because of their reasonable cost, unique properties and interdisciplinary emerging applications. The present paper reports the synthesis of aluminium nanoparticles in the mixture of Deionized water (DI water) and Polyethylene Glycol (PEG) using a developed micro-Electrical Discharge Machining (μ-EDM) method. PEG was used as a stabilizer to prevent nanoparticles from agglomeration produced during the μ -EDM process. The synthesized aluminium nanoparticles were examined by Transmission Electron Microscopy (TEM), Energy Dispersive Analysis by X-rays (EDAX) and Selected Area Electron Diffraction (SAED) pattern to determine their size, shape, chemical nature and crystal structure. The average size of the polyhedral aluminium nanoparticles is found to be 196 nm.

Enhanced acetone sensing performance of nanostructured Sm2O3 doped SnO2 thick films

In the present work, we synthesized Sm2O3 doped SnO2 in order to prepare a selective acetone sensor with fast response, quick recovery and good repeatability. Pure as well as 2 mol.%, 4 mol.%, 6 mol.% and 8 mol.% Sm2O3 doped SnO2 nanostructured samples were synthesized by using a co-precipitation method. The characterization of the samples was done by thermogravimetric and differential thermo-gravimetric analysis (TG-DTA), X-ray diffraction (XRD), field emission gun-scanning electron microscopy (FEG-SEM), energy dispersive analysis by X-rays (EDAX), high resolution scanning electron microscopy (HR-TEM), selected area X-ray diffraction (SAED), Brunauer-Emmet-Teller (BET) and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy techniques. The gas response studies of liquid petroleum gas, ammonia, ethanol and acetone vapor were carried out. The results showed that Sm doping systematically lowered operating temperature and enhanced the gas response and selectivity for acetone. The response and recovery time for 6 mol.% Sm2O3 doped SnO2 thick film at the operating temperature of 250 °C were 15 and 24 s, respectively.

Tribological Properties of Composites for Brake Lining Application - AReview

Wear takes predominant role in reducing the cutting life time of brake lining materials. This work focuses on the influence of nanoparticle on the tool material. Nanoparticle powder was coated on the high speed composite pin by using physical vapour deposition (PVD) technique. The stainless steel was selected as a disc work piece material. The performance parameters like volume loss, wear rate, stresses developed and temperature rise were compared between coated high speed steel pin and uncoated high speed steel pin upon machining the stainless steel disc. The performance parameters were calculated by using coefficient of friction values which were obtained from the pin on disc test. Substantial resistance to wear has been achieved by the coating. Scanning electron microscope (SEM) Analysis and Energy dispersive analysis by X-ray (EDAX) were used as characterization techniques.

Synthesis, characterization and enhanced acetone sensing performance of Pd loaded Sm doped SnO2 nanoparticles

Abstract In the present communication, we have presented a high performance acetone sensor based on Pd loaded Sm doped SnO 2 nanomaterial. The (0.5, 1, 2 and 3) wt% Pd loaded 6 mol% Sm doped SnO 2 nanoparticles were prepared using a co-precipitation method. The characterization of samples was done by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FEG-SEM), Energy Dispersive Analysis by X-rays (EDAX), High Resolution-Transmission Electron Microscopy (HR-TEM) and Selective Area Electron Diffraction (SAED) techniques. The gas response studies such as sensitivity, selectivity and stability towards liquid petroleum gas, ammonia, ethanol and acetone were measured at 100 ppm concentrations. The results show that optimum Pd loading (2 wt%) results in smaller crystallite size (~3.1 nm), lower operating temperature (200 °C), higher gas response (94%),better selectivity, faster response (~3 s) and quicker recovery (~12 s) towards acetone.

Effect of annealing on the properties of spray-pyrolysed lead sulphide thin films for solar cell application

Annealing is the most important processing parameter perhaps as it directly affects the properties of the thin films. In the present article, lead sulphide thin films composed of (2 0 0) plane-oriented nano-rods were successfully synthesized on glass substrates using spray pyrolysis technique at annealing temperature 350 °C. Films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive analysis by X-ray (EDAX), UV–VIS–NIR spectrometry and two-probe experiments. The X-ray diffraction study confirmed that films exhibiting face-centred cubic structure with a preferred orientation along (2 0 0) plane were independent of annealing temperature. SEM photographs revealed the formation of nano-rods. The possible formation of nano-rods and its dependency on optical and electrical properties were discussed. Chemical composition in terms of atomic ratio of the constituents is determined from EDAX studies. The optical band gap of the lead sulphide thin films was found to decrease from 1.22 to 0.98 eV with an increase in annealing temperature. The electrical conductivity of the films at room temperature was of the order of 10−2 Ω−1 cm−1 with the low activation energy. Results prove that lead sulphide films grown by chemical method appeal its adoptability for potential solar cell applications.

Characterizations of Thermal Compound Using CuO Particles Grown by Wet Oxidation Method

Various morphologies of copper oxide (CuO) have been considered to be of both fundamental and practical importance in the field of electronic materials. In this study, using Cu (0.1 μm and 7 μm) particles, flake-type CuO particles were grown via a wet oxidation method for 5min and 60min at 75 °C. Using the prepared CuO, AlN, and silicone base as reagents, thermal interface material (TIM) compounds were synthesized using a high speed paste mixer. The properties of the thermal compounds prepared using the CuO particles were observed by thermal conductivity and breakdown voltage measurement. Most importantly, the volume of thermal compounds created using CuO particles grown from 0.1 μm Cu particles increased by 192.5% and 125 % depending on the growth time. The composition of CuO was confirmed by X-ray diffraction (XRD) analysis; cross sections of the grown CuO particles were observed using focused ion beam (FIB), field emission scanning electron microscopy (FE-SEM), and energy dispersive analysis by X-ray (EDAX). In addition, the thermal compound dispersion of the Cu and Al elements were observed by X-ray elemental mapping.

Screening of solid base catalysts on palm oil based biolubricant synthesis

The activity of solid base catalysts with selected dopants on the synthesis of trimethylolpropane triesters (TMPTE) biolubricant from palm oil methyl esters (POME) was performed in this study. The morphological and structural studies of synthesized catalysts were carried out using field emission scanning electron microscopy, X-ray diffraction (XRD), temperature programmed desorption (TPD-CO2), fourier transform infrared spectroscopy (FTIR), energy dispersive analysis by X-ray (EDX) and Brunauer–Emmett–Teller (BET) and gas chromatography (GC). The effects of temperature, time and the catalyst amount on the catalytic performance of different solid base catalyst with selected dopants were appraised. Under the optimized reaction conditions of 1 %w/w mixed oxides of Ca and Sr catalyst with 5 %w/w SrO on CaO, at 180 °C, 2 mbar vacuum pressure and 240 min of reaction time, TMPTE was successfully synthesized with 88% of yields. The type of metal oxide and mixed metal oxides demonstrated a significant effect on the physical property of the catalyst and its catalytic activity.

Effect of precursor concentration on physical properties of nebulized spray deposited In2S3 thin films

The present work investigates the effect of precursor concentration (mc) on the structural, optical, morphological and electrical conductivity properties of In2S3 thin films grown on amorphous glass substrates by nebulized spray pyrolysis (NSP) technique. The mixed phase of cubic and tetragonal structure of In2S3 thin films at higher concentration has been observed by X-ray diffraction pattern. The reduced strain by increasing the precursor concentration increased the average crystallite from 17.8 to 28.9 nm. The energy dispersive analysis by X-ray (EDAX) studies confirmed the presence of In and S. The transmittance, optical direct band gap energy, Urbach energy and skin depth of In2S3 films have been analyzed by optical absorption spectra. The better conductivity and mobility noticed at mc = 0.15 M are explained by carrier concentration and crystallite. Better optical and electrical conductivity behaviour of In2S3 thin film sample proposes for effective solar cell fabrication.

Optical and electrical properties of In4Se96-xSx chalcogenide thin films

The objective is to study the physical, structural, compositional, electrical and optical changes in InSeS alloy. In4Se96-xSx (where x = 0, 4, 8, 12) chalcogenide semiconductors has been deposited on non-conducting glass substrate by thermal evaporation technique at a pressure of approximately 10−6 Torr. The thin films were characterized by XRD, SEM, UV spectroscopy and electrical measurement. XRD shows the amorphous nature of the prepared thins films. Surface morphological analysis were carried out by scanning electron microscope (SEM), which shows the grain development of the prepared samples. Energy dispersive analysis by X-ray (EDAX) was used to check the compositional elements of deposited films. The analysis of the absorption spectra show indirect band gap, the magnitude of optical band gap increases and the corresponding absorption coefficient decreases with Sulfur concentration. The temperature dependent DC Conductivity (σdc) decreases and the corresponding activation energy increases with increase of Sulfur content for the In4Se96-xSx. High field conduction study shows the space charge limited conduction (SCLC) is dominated from where the density of states has been evaluated, density of state decreases with increases of sulfur concentration which may be due to decrease in disorderness or decrease in defects states of the system.

Influence of substrate temperature on physical properties of (111) oriented CdIn2S4 thin films by nebulized spray pyrolysis technique

In this work, we present the substrate temperature influenced change in the structural, optical, morphological, and electrical conductivity properties of CdIn2S4 thin films deposited on amorphous glass substrates by nebulized spray pyrolysis (NSP) technique. X-ray diffraction pattern revealed that the as-deposited CdIn2S4 thin films had a cubic structure with a preferred orientation along (111) plane. The reduced strain by increasing the substrate temperature from 200 to 350 °C increased the average crystalline size from 17 to 33 nm while the formation of secondary phases such as CdIn2O4 and In2O3 reduced it to 21 nm after the substrate temperature at 450 °C. The energy dispersive analysis by X-ray (EDAX) studies confirmed the presence of Cd, In, and S. The absorption coefficient, direct band gap energy, Urbach energy, skin depth, and extinction coefficient of CdIn2S4 films were analyzed by optical absorption spectra. The better conductivity and mobility noticed at Ts = 350 °C are explained by carrier concentration and crystalline size. Better optical and electrical conductivity behavior of CdIn2S4 thin film sample suggests for effective PEC solar cell fabrication.

Studies on structural, optical, mechanical properties of undoped and doped l-histidine monohydrate monohydrochloride(LHMHCL)

Single crystals of l-histidine monohydrate monohydrochloride (LHMHCL), semi organic crystal were grown by slow evaporation technique. The grown crystals were subjected to various studies such as single crystal X-ray diffraction (XRD), Powder XRD, UV-vis studies, Fourier transform infrared (FTIR), Energy dispersive analysis by X-rays (EDAX). Single crystal X-ray diffraction studies reveals the crystal belong to orthorhombic crystallographic system.

Characterization of jet nebulizer sprayed CdO thin films for solar cell application

The highly transparent conducting cadmium oxide (CdO) films were prepared by jet nebulizer spray pyrolysis. Characterization and optimization of CdO films have been scrutinized using various techniques such as X-ray diffraction (XRD) pattern, scanning electron microscope (SEM), energy dispersive analysis by X-ray (EDAX) spectroscopy, Atomic force microscopy (AFM), ultraviolet visible (UV-Vis) spectroscopy, hall Effect and current–voltage (I–V) characteristics. The sample prepared at 400°C with 4ml and 0.20M of volume and concentration of the precursor solution respectively have the transmittance of about 70% with a band gap of 2.37eV and the resistivity was found to be a minimum of 3.38×10−3Ωcm. The XRD, SEM and AFM studies have implied the presence of CdO nanocrystallites with cubic structure and having smooth surface. The short circuit current (Isc)=5.90mA/cm2 and open circuit volatge (Voc)=429.3mV values were established to be the maximum for the cell made with CdO films at 400°C. The fill factor (FF)=0.32 and conversion efficiency η=0.8% was also maximum for this solar cell. The low fill factor and efficiency might be due to the formation of excess silicon dioxide (SiO2) at the CdO/p-Si interface due to reaction between CdO and Si at 400°C.

Effect of Se addition on optical and electrical properties of chalcogenide CdSSe thin films

Compositional dependence of optical and electrical properties of chalcogenide CdSxSe1−x (0.4≥x≥0.0 at. %) thin films was studied. Cadmium sulphoselenide films were deposited by thermal evaporation technique at vacuum (8.2×10−4 Pa) onto preheated glass substrates (523 K). The evaporation rate and film thickness were kept constant at 2.50 nm/s and 375 ± 5 nm, respectively. X-ray diffractograms showed that, the deposited films have the low crystalline nature. Energy dispersive analysis by X-ray (EDAX) was used to check the compositional elements of deposited films. The absorption coefficient was determined from transmission and reflection measurements at room temperature in the wavelength range 300–2500 nm. Optical density, skin depth, optical energy gap and Urbach's parameters of CdSSe thin films have also been estimated. The direct optical energy gap decreased from 2.248 eV to 1.749 eV when the ratio of Se-content was increased from 0.60 to 1.00 . Conduction band and valance band positions were evaluated. The temperature dependence of dc-electrical resistivity in the temperature range (293–450 K) has been reported. Three conduction regions due to different conduction mechanisms were detected. Electrical sheet resistance, activation energy and pre-exponential parameters were discussed. The estimated values of optical and electrical parameters were strongly dependent upon the Se-content in CdSSe matrix.

Synthesis, characterization and optical properties of polymer‐based ZnS nanocomposites

Nanostructured polymer-semiconductor hybrid materials such as ZnS-poly(vinyl alcohol) (ZnS-PVA), ZnS-starch and ZnS-hydroxypropylmethyl cellulose (Zns-HPMC) are synthesized by a facile aqueous route. The obtained nanocomposites are characterized using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV/vis spectroscopy and photoluminescence (PL). XRD studies confirm the zinc blende phase of the nanocomposites and indicate the high purity of the samples. SEM studies indicate small nanoparticles clinging to the surface of a bigger particle. The Energy Dispersive Analysis by X-rays (EDAX) spectrum reveals that the elemental composition of the nanocomposites consists primarily of Zn:S. FTIR studies indicate that the polymer matrix is closely associated with ZnS nanoparticles. The large number of hydroxyl groups in the polymer matrix facilitates the complexation of metal ions. The absorption spectra of the specimens show a blue shift in the absorption edge. The spectrum reveals an absorption edge at 320, 310 and 325 nm, respectively. PL of nanocomposites shows broad peaks in the violet-blue region (420-450 nm). The emission intensity changes with the nature of capping agent. The PL intensity of ZnS-HPMC nanocomposites is found to be highest among the studied nanocomposites. The results clearly indicate that hydroxyl-functionalized HPMC is much more effective at nucleating and stabilizing colloidal ZnS nanoparticles in aqueous suspensions compared with PVA and starch.

Microstructure and crystal imperfections of nanosized CdSxSe1−x thermally evaporated thin films

Cadmium sulfoselenide CdSxSe1−x thin films were thermally evaporated onto preheated glass substrates (523K). The evaporation rate and film thickness were kept constant at ≈2.5nm/s and 375±5nm, respectively. Microstructure and crystal imperfections of deposit CdSxSe1−x thin films were studied using X-ray diffraction (XRD) and energy dispersive analysis by X-ray (EDAX). XRD analysis reveals the formation of films have the semi-crystalline nature and the hexagonal structure with preferential 〈002〉 direction. The microstructural parameters such as, lattice parameters, the crystallite size (D), microstrain 〈ε〉, residual internal stress (S), dislocation density (δ) and number of crystallite per unit volume (N) were calculated and found to be dependent upon the composition. The presence percentage of Cd, S and Se elements in the chalcogenide CdSxSe1−x thin films were estimated by EDAX and a comparative study with other similar samples of the previous literature was discussed.

Vertical current-flow enhancement via fabrication of GaN nanorod p–n junction diode on graphene

Mg doped GaN nanorods were grown on undoped n-type GaN nanorods uniaxial on monolayer graphene by hydride vapor phase epitaxy (HVPE) method. The monolayer graphene used as the bottom electrode and a substrate as well provides good electrical contact, acts as a current spreading layer, well suitable for the growth of hexagonal GaN nanorod. In addition it has a work function suitable to that of n-GaN. The formed p–n nanorods show a Schottky behavior with a turn on voltage of 3V. Using graphene as the substrate, the resistance of the nanorod is reduced by 700 times when compared with the case without using graphene as the current spreading layer. The low resistance of graphene acts in parallel with the resistance of the GaN buffer layer, and reduces the resistance drastically. The formed p–n junction in a single GaN nanorod is visualized by Kelvin Force Probe Microscopy (KPFM) to have distinctively contrast p and n regions. The measured contact potential difference of p-and n-region has a difference of 103mV which well confirms the formed regions are electronically different. Low temperature photoluminescence (PL) spectra give evidence of dopant related acceptor bound emission at 3.2eV different from 3.4eV of undoped GaN. The crystalline structure, compositional purity is confirmed by X-ray diffraction (XRD), Transmission and Scanning electron microcopies (SEM), (TEM), Energy dispersive analysis by X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS) as well.

Studies on sulfur doping and figure of merit in vapor grown Sb2Te3 platelet crystals

A series of p-type Sb2Te3−xSx (x=0, 0.1, 0.2, 0.3 and 0.4) samples for each sulfur composition was vapor deposited to explore the crystal growth mechanism of platelet morphology and to understand their potential use for thermoelectric devices. Structural characterization performed by X-ray diffraction exhibited consistent rhombohedral unit cell parameters for all the antimony telluride crystals with D53d space group symmetry. Scanning electron microscopy (SEM) and energy dispersive analysis by X-rays (EDAX) were employed for morphological and compositional studies. The Seebeck coefficient S (⊥c) of Sb2Te3−xSx crystals for sulfur composition, x=0.3 was remarkably improved, yielding a figure of merit (ZT)=0.54, which is ~2.5 fold rise compared to the melt grown Sb2Te3 crystals. The atomic force microscopic (AFM) imprints revealed that, with increasing content of dopant, distribution of etch pits and microhardness increased in sulfur doped crystals. By optimizing sulfur doping, the antisite (AS) defect formation can be suppressed for enhancing ZT and the results obtained enable to design novel thermoelectric materials for application in power generation and refrigeration.

Wear Analysis on Silicon Carbide Coated HSS Pin on SS Disc Substrate

Wear takes predominant role in reducing the cutting life time of tool materials. This investigation focuses on the influence of Silicon Carbide nanocoating on the HSS tool material. Silicon carbide powder was coated on the high speed steel pin by using physical vapour deposition (PVD) technique. The stainless steel was selected as a work piece material. The performance parameters like volume loss, wear rate, stresses developed and temperature rise were compared between coated high speed steel pin and uncoated high speed steel pin upon machining the stainless steel disc. The performance parameters were calculated by using coefficient of friction values which were obtained from the pin on disc test. Substantial resistance to wear has been achieved by the coating. Scanning electron microscope (SEM) Analysis and Energy dispersive analysis by X-ray (EDAX) were used as characterization techniques.

Second-order, third-order NLO and other properties of l-alanine crystals admixtured with perchloric acid (LAPA)

Nonlinear optical (NLO) single crystals of l-alanine admixtured with perchloric acid (LAPA) were grown for the first time by slow evaporation technique. The grown single crystals were subjected to different characterization analyses in order to find out its suitability for device fabrication for optoelectronic applications. Orthorhombic structure of LAPA crystal was confirmed by single crystal X-ray diffraction. The LAPA crystallizes in non-centrosymmetric structure, which is an essential criterion for second-order NLO effects. The third-order nonlinearities of LAPA crystal have been investigated by the Z-scan method. The values of nonlinear refractive index (n2), the nonlinear absorption coefficient (β) and third-order nonlinear susceptibility (χ(3)) are estimated for the sample. The grown sample was characterized by Energy Dispersive Analysis by X-rays (EDAX) to confirm the presence of elements. The optical quality was assessed by recording UV – visible transmission spectrum. Thermal behavior and thermal stability of crystal were studied using thermogravimetric/differential thermal (TG/DTA) techniques. The dielectric constant and dielectric loss have been measured for different frequencies and at different temperatures. The mechanical properties of the grown crystals were studied using Vickers microhardness tester.

Probing the dominance of interstitial oxygen defects in ZnO nanoparticles through structural and optical characterizations

ZnO nanoparticles, synthesized adopting a facile chemical precipitation route, are studied here. The structural, optical and electronic properties of prepared ZnO nanoparticles were extensively investigated employing X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive analysis by X-rays (EDAX), X-ray photoelectron spectroscopy (XPS), UV–vis absorption and fluorescence (FL) spectroscopy. The XRD analysis revealed hexagonal wurtzite phase 26.1–29.6nm size ZnO nanocrystallites. This observation gets further support from TEM images where particles of 25–30nm size are vividly seen. Interestingly, oxygen rich stoichiometry of nanoparticles is detected via zinc and oxygen emission lines of EDAX spectrum. XPS analysis establishes coexistence of lattice oxygen (OL), interstitial oxygen (Oi) and oxygen vacancy (VO) in ZnO nanoparticles. In line with EDAX analysis, XPS investigations substantiate interstitial oxygen rich composition of nanoparticles. Blue shift of absorption energy, as observed in the UV–vis spectrum of ZnO nanoparticles, typically manifests quantum confinement effect. Such transitions indicate the occurrence of various discrete energy states of prepared nanoparticles. FL spectroscopic investigations ascertain the existence of these discrete states by probing the radiative transitions arising among such states. Finally, FL study not only demonstrates visible emissions emanating from the oxygen defect states but more remarkably, in concurrence with EDAX and XPS analysis, establishes the excess of interstitial oxygen defects in prepared ZnO nanoparticles.