Energy Dispersive X-ray Powder Diffraction Research Articles

Durability of Non-Heat-Cured Geopolymer Mortars Containing Metakaolin and Ground Granulated Blast Furnace Slag

This study presents the durability, strength and microstructure of non-heat-cured geopolymer mortars (GMs) containing metakaolin (MK), ground granulated blast furnace slag (GGBFS), potassium hydroxide (KOH), sodium metasilicate (Na2SiO3), CEN sand and network water. Optimum MK, GGBFS and activator solution ratios were investigated, and the compressive strength of non-heat-cured 28-day GMs reached 55 MPa. Analysis of GMs using scanning electron microscopy (SEM), energy-dispersive X-ray spectrophotometry (EDX) and X-ray powder diffraction (XRD) revealed alumino-silicate formation, potassium from KOH solution and calcium from GGBFS. It showed that the grains containing high silica in the form of quartz crystals were found in the gel formation. The strength and durability of MK- and GGBFS-based GMs exposed to freeze–thawing, a high temperature, wear loss, magnesium sulfate (MgSO4), sodium sulfate (Na2SO4) and HCl solutions were found to be sufficient.

Studying the Possibility of Using a Carbon Sorbent Based on a Graphite Nitrate Cointercalation Compound for Water Purification from Heavy Metal Ions

The results of studies of the carbon sorbent adsorption properties by atomic absorption spectrometry are presented. Carbon sorbent was obtained by graphite nitrate cointercalation compound thermal expansion at 900 °C. It is shown that the Freundlich, Langmuir and Temkin equations adequately describe the adsorption of the studied metal ions by a carbon sorbent. The carbon sorbent after the adsorption of heavy metal ions was studied using energy-dispersive X-ray spectrometry and X-ray powder diffraction. The limit values were fixed for the adsorption capacity of the sorbent relative to Cu2+, Ni2+, Fe2+ as 0.94; 0.85 and 0.58 mmol/g sorbent, respectively. It was concluded that the conducted studies indicate the possibility of using such sorbent in processes of water purification from heavy metal ions.

Nitride Synthesis under High-Pressure, High-Temperature Conditions: Unprecedented In Situ Insight into the Reaction.

High-pressure, high-temperature (HP/HT) syntheses are essential for modern high-performance materials. Phosphorus nitride, nitridophosphate, and more generally nitride syntheses benefit greatly from HP/HT conditions. In this contribution, we present the first systematic in situ investigation of a nitridophosphate HP/HT synthesis using the reaction of zinc nitride Zn3N2 and phosphorus(V) nitride P3N5 to the nitride semiconductor Zn2PN3 as a case study. At a pressure of 8 GPa and temperatures up to 1300 °C, the reaction was monitored by energy-dispersive powder X-ray diffraction (ED-PXRD) in a large-volume press at beamline P61B at DESY. The experiments investigate the general behavior of the starting materials under extreme conditions and give insight into the reaction. During cold compression and subsequent heating, the starting materials remain crystalline above their ambient-pressure decomposition points, until a sufficient minimum temperature is reached and the reaction starts. The reaction proceeds via ion diffusion at grain boundaries with an exponential decay in the reaction rate. Raising the temperature above the minimum required value quickly completes the reaction and initiates single-crystal growth. After cooling and decompression, which did not influence the resulting product, the recovered sample was analyzed by energy-dispersive X-ray (EDX) spectroscopy.

Carvacrol Encapsulation in Chitosan-Carboxymethylcellulose-Alginate Nanocarriers for Postharvest Tomato Protection.

Advancements in polymer science and nanotechnology hold significant potential for addressing the increasing demands of food security, by enhancing the shelf life, barrier properties, and nutritional quality of harvested fruits and vegetables. In this context, biopolymer-based delivery systems present themselves as a promising strategy for encapsulating bioactive compounds, improving their absorption, stability, and functionality. This study provides an exploration of the synthesis, characterization, and postharvest protection applications of nanocarriers formed through the complexation of chitosan oligomers, carboxymethylcellulose, and alginate in a 2:2:1 molar ratio. This complexation process was facilitated by methacrylic anhydride and sodium tripolyphosphate as cross-linking agents. Characterization techniques employed include transmission electron microscopy, energy-dispersive X-ray spectroscopy, infrared spectroscopy, thermal analysis, and X-ray powder diffraction. The resulting hollow nanospheres, characterized by a monodisperse distribution and a mean diameter of 114 nm, exhibited efficient encapsulation of carvacrol, with a loading capacity of approximately 20%. Their suitability for phytopathogen control was assessed in vitro against three phytopathogens-Botrytis cinerea, Penicillium expansum, and Colletotrichum coccodes-revealing minimum inhibitory concentrations ranging from 23.3 to 31.3 μg·mL-1. This indicates a higher activity compared to non-encapsulated conventional fungicides. In ex situ tests for tomato (cv. 'Daniela') protection, higher doses (50-100 μg·mL-1, depending on the pathogen) were necessary to achieve high protection. Nevertheless, these doses remained practical for real-world applicability. The advantages of safety, coupled with the potential for a multi-target mode of action, further enhance the appeal of these nanocarriers.

Composition-adjustable silicon-germanium alloy films based on porous silicon matrices

Morphology and crystalline structure of silicon-germanium alloys formed by rapid thermal processing of germanium-filled porous silicon layers are evaluated. Two types of porous silicon are employed as matrices for electrochemical pore filling using GeO2 aqueous solutions and subsequently compared, the first one formed by electrochemical anodization and the second by silver-assisted chemical etching of monocrystalline silicon. The resulting alloys’ structure and composition are investigated using scanning electron microscopy, energy-dispersive X-ray analysis, Raman spectroscopy and X-ray powder diffraction. It is shown that by varying the porosity of the initial matrix (by adjusting anodization current density for anodic porous silicon or changing silver deposition time for structures produced by metal-assisted etching) in the range from 55 to 75%, Si1-xGex alloys with germanium fractions of x = 0.31 to x = 0.83 can be formed, as indicated by Raman spectroscopy. It is concluded that composition-adjustable layers of silicon-germanium can be successfully formed on either type of porous silicon layer. While an increase in porosity generally leads to a decrease in silicon fractions in the alloy, the steepness of this effect varies heavily depending on the type of porous matrix used and should be considered independently for anodic porous silicon and silicon nanowires.

Insights into the foulants characteristics in a walnut shell biofilm-membrane bioreactor during treatment of hypersaline oilfield produced water

The characteristics and behavior of membrane fouling in oilfield produced water treatment systems are highly affected by the complex nature of this stream. The present study is dedicated to the characterization of the membrane foulants in a hybrid moving bed and membrane bioreactor (MBBR-MBR) system using walnut shell as a bio-carrier, for treatment of real produced water at total dissolved solids (TDS) concentrations of 35,000, 90,000 and 200,000 mg/L. The impact of using walnut shell on fouling was also investigated. Various analytical methods including attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), gas chromatography- mass spectrometry (GC–MS) were used to identify the organic compounds and inductively coupled plasma- optical emission spectrometry (ICP- OES), X-ray fluorescence (XRF), energy-dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRD) were applied in order to investigate the inorganic constituents present in the foulants. Additionally, field emission scanning electron microscopes (FE-SEM), atomic force microscopy (AFM) and particle size distribution (PSD) analysis were used as auxiliary tools to investigate the morphology and particle size distribution of the cake layer. The results indicated that the most important organic compounds identified included microorganisms, microbial products, and hydrocarbons. Also, the most important inorganic elements included Na, Cl, K, Ca, S, and P which probably originated from NaCl, CaCO3, and Ca-P precipitates. Walnut shell was effective in reducing membrane fouling due to the scouring effect, as well as altering the properties of sludge, and adsorption of oil compounds.

Ethanothermal Synthesis of Octahedral-Shaped Doped Mn2O3 Single Crystals as a Precursor for LiMn2O4 Spinel Cathodes in Lithium-Ion Batteries

Micrometer-sized particles of single-crystalline octahedral-shaped Mn2O3 doped with various elements (Al, Ti, Ni, and Zr) have been obtained by an ethanothermal synthesis at 150 °C. The doping of other element(s) into the Mn2O3 framework is characterized by energy-dispersive X-ray spectroscopy and X-ray powder diffraction. With Ni as a dopant, however, the particle morphology changed dramatically to spheres. The doped Mn2O3 with octahedral morphologies was employed as a precursor for the preparation of doped spinel LiMn2O4 cathodes for lithium-ion batteries. The doped samples exhibit enhanced cycle life, with the Al and Ti codoped sample displaying ∼90% capacity retention after 100 cycles at C/3 rate in full cells with a graphite anode. In addition, replacing 25 vol % of ethanol with water as the solvent for the solvothermal synthesis gives a rod-shaped γ-MnOOH structure instead of α-Mn2O3, which will be attractive for future studies of unique physicochemical properties originating from the shape.

MAPb(Br1–xClx)3 Hybrid Perovskite Materials for Direct X-ray Detection

The study and development in recent years of hybrid (organic–inorganic) halide perovskite materials have given them an unprecedented opportunity for direct ionizing radiation detection, given their large attenuation coefficient and sufficient charge carrier mobility lifetime product. The use of single crystals, considered as model materials, allows us to investigate their intrinsic properties. Characterizations under X-ray illumination of detector devices based on methylammonium lead tribromide (MAPbBr3) single crystals, obtained by optimized growths, show good sensitivity but high dark current density. To improve this critical parameter, while using MAPbBr3 as the base material, we employ anion engineering within the halide elements. We present here mixed halide perovskite crystals, with bromide partially replaced with chloride, obtained through optimized growths using modified inverse temperature crystallization in dimethylformamide, leading to high-quality single crystals of the general formula MAPb(Br1–xClx)3. Six chlorine contents are targeted and carefully determined experimentally via energy-dispersive X-ray analysis and X-ray powder diffraction. For each composition, several crystals are synthesized and used to prepare X-ray detection devices. Their optoelectronic properties are determined under standard X-ray medical conditions and hint at the existence of an optimal composition. MAPb(Br0.85Cl0.15)3 exhibits the best sensitivity with a value of S ≈ 3 μC mGyair–1 cm–2 for RQA5 spectral quality and the lowest dark current density with a value of Jdark ≈ 22 nA mm–2, both recorded at a 50 V mm–1 electric field. This sensitivity value doubles our own MAPbBr3 single crystal device and is higher than that of CsI(Tl)- or a-Se-based flat panels. The present work broadens the benefits and drawbacks of employing halide engineering in perovskite materials to improve the optoelectronic performance under high-energy radiation.

Investigation of calcium-silicate content and conversion degree of resin-based pulp capping materials

The present study aimed to measure the microstructure of the TheraCal LC (Bisco Inc., Schaumburg, IL) and Calciplus LC (Imicryl, Konya, Turkey) and to investigate the effect of excitation durations and different light sources on their ‘degree of conversion’ properties. Three excitation modes of the resinous pulp capping materials were tested at 5, 10, and 20-s: light-emitting diode, and near-infrared laser excitation at 532 and 785 nm wavelengths. Resinous materials and excitation durations factors were analyzed with the two-way ANOVA test and Tukey Post Hoc tests (α = 0.05). It is found that the near-infrared laser cannot polymerize the samples and TheraCal LC had greater mean values than Calciplus LC at 5, 10, and 20-s (p < 0.001, p = 0.011, and p = 0.062, respectively). Energy-dispersive X-ray spectroscopy and X-ray powder diffraction analysis were used to assess the calcium-silicate content. Calcium-silicate phases were observed in TheraCal LC but these phases did not exist in the Calciplus LC. TheraCal LC and Calciplus LC have similarities in their conversion degree properties with LED excitations at 20-s, however, the calcium-silicate content measured in the experiments is not in agreement with the data of the Calciplus LC declared by the manufacturer.

Mechanism of Be-Thermodiffusion in Rutile Inclusions of Fancy Sapphires

The solid-state chemistry of inclusions in Al2O3 is of high relevance in several applications, spanning from photonics to materials engineering and gemology. Be-thermodiffusion is a common treatment of corundum crystals to improve their optical properties. The chemistry of such a high-temperature process is still unclear. Particularly, the interconversion between corundum host and guest inclusion species involves many chemical species and several steps, whose knowledge would guide the tuning of corundum chemical preparation. Herein, 43 thermodiffusion-treated sapphires are investigated, with a focus on 14 samples endowed with blue halos, via optical microscopy, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) quantitative chemical analyses, Raman microspectroscopy, and X-ray powder diffraction. This study searches for the snapshots of the chemical path and then recomposes them to propose a novel chemical mechanism in which Be reduces TiO2 inclusion, which is then converted, mediated by iron ions, to several titanates. The chemical mechanism is discussed in terms of applications not limited to only gemology but to any derivative corundum crystal preparation.

Efficient removal of non-steroidal anti-inflammatory ibuprofen by polypyrrole-functionalized magnetic zeolite from aqueous solution: kinetic, equilibrium, and thermodynamic studies

ABSTRACT This study investigated the adsorption performance of ibuprofen onto magnetic zeolite clinoptilolite modified with polypyrrole (Clino/Fe3O4/Ppy). The synthesized nanocomposite was characterized by scanning electron microscope, Fourier-transform infrared spectroscopy, Energy-dispersive X-ray analysis, Brunauer-Emmett-Teller, and X-ray powder diffraction analysis. The obtained results demonstrated that the high surface area of zeolite could significantly impact the adsorption process. Various parameters were studied to determine the optimum condition, including contact time, pH, adsorbent dosage, initial ibuprofen concentration, temperature, and mixing speed. The optimization of contact time revealed a high performance in the first 5 min of the adsorption process. Furthermore, when the temperature rose, the efficiency increased as well, with the highest efficiency being achieved at 45°C. Some isotherm models and kinetics equations were used to analyze equilibrium data. The kinetic study revealed that the adsorption process followed pseudo-second-order (R2 = 0.9972), and the isotherm investigations showed that Langmuir (R2 = 0.9941) was an appropriate model for explaining the equilibrium of the adsorption process. Based on the obtained thermodynamic factors, it was represented that the adsorption process was endothermic and spontaneous. Based on the research findings, Clino/Fe3O4/PPy nano-adsorbent developed in this study might be a helpful strategy for removing ibuprofen from various water sources.

Potential Toxicity of Natural Fibrous Zeolites: In Vitro Study Using Jurkat and HT22 Cell Lines

An emerging problem for human health is the exposure to non-regulated mineral fibers with an asbestos-like crystal habit, particularly fibrous zeolites. This study aimed to determine if and how selected fibrous zeolites (erionite, mesolite, and thomsonite) induce toxicity effects on two different in vitro cellular models, the adherent murine hippocampal (HT22) and human immortalized T lymphocyte (Jurkat) cell lines. Before proceeding with the cellular tests, the three zeolite samples were investigated using scanning electron microscopy–energy-dispersive spectroscopy and X-ray powder diffraction techniques. The cells were treated with 0.1 µM and 1 µM of fibrous erionite, mesolite, and thomsonite for 12, 24, and 48 h. Results showed a cytotoxic effect of erionite in both cellular models and revealed different toxic behaviors of the mesolite and thomsonite fibers, suggesting other potential mechanisms of action. The outcome of this study would be a first step for further research on fine biochemical interactions of zeolite fibers with cells and future in vivo investigations.

Design and fabrication of electrochemical sensor based on molecularly imprinted polymer loaded onto silver nanoparticles for the detection of 17-β-estradiol.

In this research report, we prepared an electrochemical sensor based on the molecularly imprinted poly(p-aminophenol) supported by silver nanoparticles capped with 2-mercaptobenzoxazole for the selective and sensitive detection of endocrine disrupting 17-β-estradiol (E2). The electropolymerization of the functional monomer prepared the proposed molecularly imprinted polymer (MIP) composite-based sensor in the presence of E2 as a template. The recognition materials were characterized using Fourier transform infrared, cyclic voltammetry (CV), square wave voltammetry (SWV), scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray powder diffraction techniques. The electrochemical measurements were performed by employing both CV and SWV methods. We did the optimization of critical parameters affecting the sensor performances through the experimental design and verification. The developed sensor showed a linear range from 10 pM to 100 nM with the calculated quantification and detection limits of 1.86 and 6.19 pM, respectively. The incorporation of AgNP with high electrical conductivity into the MIP matrix enhanced the sensor's performance. Furthermore, the sensor was applied to determine E2 in real water samples without any sample preconcentration steps to achieve the percent recovery of 91.87% to 98.36% and acceptable reusability and storage stability performances.

Preliminary Mineralogical Characterization of Branching Selenite Gypsum: New Insights for the Paleoenvironmental Reconstruction and Mechanical Characterization

The present study proposes a characterization of textural and mineralogical features of branching selenite gypsum lithofacies from the Monferrato area (NW Italy). This facies is considered to have appeared during the sequence of the primary lower gypsum of the Messinian Salinity Crisis starting from the sixth stratigraphical cycle, providing a useful tool for stratigraphic correlation throughout the Mediterranean. It is often associated with thick and continuous beds that are exploited by open-pit and underground quarries. We provide the results of a characterization of the non-gypsum minerals that represent approximately 10% in weight of the rock. Mineralogical data were collected with energy-dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRPD) techniques. In addition, a detailed characterization of clay families was performed through dedicated XRPD analyses. Results highlight the presence of detrital minerals (quartz, feldspars and clay minerals), calcite, dolomite and epsomite. Clay analysis registered the existence of five different families (illite, chlorite, smectite and two mixed layers). These mineralogical data suggest that the origin of this lithofacies is connected to both depositional processes and in situ precipitation processes under different conditions of saturation of the brine (respectively undersaturated and supersaturated in sulfates). The mineralogical and textural heterogeneity also represents an important element in controlling the mechanical response of the material and the consequent stability of quarry sites.

Low Au-content CoAu electrodes for environmental applications.

Six cobalt gold (CoAu) electrodes were prepared by electroless deposition using different gold-containing solutions (acidic and weakly acidic) and different Au deposition times. Characterization of CoAu electrodes was done by scanning electron microscopy with energy-dispersive X-ray spectroscopy, N2-sorption, and X-ray powder diffraction techniques. The possibility of using the prepared electrodes in environmental applications, i.e., for the electrochemical sensing of a trace amount of arsenic(iii) in weakly alkaline media was assessed. Employing the CoAu electrode (prepared by immersing Co/Cu into 1 mM HAuCl4 (pH 1.8) at 30 °C for 30 s) under optimized conditions (deposition potential −0.7 V and deposition time of 60 s), a low limit of detection of 2.16 ppb was obtained. Finally, this CoAu electrode showed activity for arsenic oxidation in the presence of Cu(ii) as a model interferent as well as in real samples. Furthermore, the use of CoAu electrode as an anode in fuel cells, namely, direct borohydride – hydrogen peroxide fuel cells was also assessed. A peak power density of 191 mW cm−2 was attained at 25 °C for DBHPFC with CoAu anode at a current density of 201 mA cm−2 and cell voltage of 0.95 V, respectively. The peak power density further increased with the increase of the operating temperature to 55 °C.

Integration of cascaded aeration and neutralization for the treatment of acid mine drainage: Insights into the formation of jarosite

Acid mine drainage (AMD) treatment has become a major environmental issue confronting the global mining industry. For treating AMD economically and efficiently, a novel AMD passive treatment system consisting of cascaded aeration based biomineralization process driven by Acidithiobacillus ferrooxidans (A. ferrooxidans) LX5 followed by lime neutralization was developed. Compositions and structures of precipitates were measured through a scanning electron microscope equipped with an energy-dispersive X-ray spectrometry (SEM-EDS) and X-ray powder diffraction (XRD). Results showed that the biogenic Fe-minerals, with 1–1.5 μm diameter and 17.5 m2/g specific surface area, belonged to jarosite expressed as KFe3(SO4)2(OH)6 with Fe/S molar ratios between 1.61 and 1.68. The density and Fe2+ bio-oxidation rate of A. ferrooxidans LX5 immobilized on the surface of jarosite (namely immobilized cells) were approximately 8.3 × 108 cells/g and 7.3 mmol L−1 h−1, which were approximately 10 and 2.2 times higher than those of cultivating A. ferrooxidans LX5 solution used as the control (namely suspension cells). The constructed water-dropping system could supply sufficient oxygen for the Fe2+ bio-oxidation. The initial Fe2+ in the AMD was completely oxidized into Fe3+ and 41.8% of total Fe was removed during biomineralization. In addition, it was found that 34% of Zn2+, 21% of Cd2+, 42.7% of Cr3+, and 23.8% of Cu2+ were removed by co-precipitation or adsorption to jarosite simultaneously. With this novel treatment system, the amounts of lime addition required for AMD neutralization and toxic solid waste production were drastically decreased by about 70 wt% and 81.3 wt%, respectively, in comparison to the control (without biomineralization). These results show water-dropping aeration and A. ferrooxidans LX5 play a significant role in the Fe2+ bio-oxidation and removal of metal ions, and the integration of cascaded aeration and neutralization is a possibility for cost-effective treatment of highly acid and toxic metal-loaded AMD.

Optimisation of chemical constituents on enzyme-induced carbonate precipitation in test-tube and soil

Enzyme-induced carbonate precipitation (EICP) is a bio-cementation technique and a sustainable method of ground improvement. This study examines the influence of the concentrations of substrates [S 0] and enzymes [E 0] as well as enzyme activity (A E) on the calcium carbonate (CaCO3) precipitation ratio (PR) using 130 test-tube experiments. It was found that the effect of enzyme concentration and activity on PR can be explained using a normalisation of [E s] = [E 0] × A E, where [E s] is the adjusted enzyme concentration. PR increased non-linearly with increasing [E s]/[S 0] and reached 100% at a threshold [E s]/[S 0] value of approximately 20 kU/mol. An exponential function was developed that could capture the relationship between PR and [E s]/[S 0] with reasonable accuracy. This observation was further evaluated with data from the literature consisting of a further 100 test-tube experiments. EICP solutions consisting of [E s]/[S 0] = 20 kU/mol were found to be optimum for soil treatment. The established function was later extended to predict strength gain as measured by the unconfined compressive strength (UCS) and the splitting tensile strength (STS) for EICP-treated soils and could predict the strength gain (UCS/STS) with reasonable accuracy. Results from scanning electron microscopy images, energy-dispersive X-ray spectroscopy and X-ray powder diffraction showed that the precipitated calcium carbonate in test tubes and treated soil was mostly calcite crystals with different morphologies, possibly due to the level of purity of the urease enzyme used.

Simple New Method for the Preparation of La(IO3)3 Nanoparticles.

We present a cost- and time-efficient method for the controlled preparation of single phase La(IO3)3 nanoparticles via a simple soft-chemical route, which takes a matter of hours, thereby providing an alternative to the common hydrothermal method, which takes days. Nanoparticles of pure α-La(IO3)3 and pure δ-La(IO3)3 were synthesised via the new method depending on the source of iodate ions, thereby demonstrating the versatility of the synthesis route. The crystal structure, nanoparticle size-dispersal, and chemical composition were characterised via angle- and energy-dispersive powder X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy.

Tribological Behavior of Magnesium Hybrid Composite: Effect of Amorphous Silica-Solid Waste Reinforcement Particles to Reduce Material Cost

Reducing weight is a crucial factor in automobile industries for structural applications. Waste management includes the collection of storage and recycling of waste. Indians are producing around 230 million tons of waste a year because of the world’s largest population. An attempt was made in varying weight fractions to develop magnesium hybrid composites using the powder metallurgy (P/M) technique. The mechanical properties like micro-hardness, tensile, impact strength are analyzed. The size distribution and physical properties like FTIR, density are tested for magnesium hybrid composites. Microstructure analysis is taken using a scanning electron microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDS) and X-ray powder diffraction (XRD) are analyzed. The waste materials are not only found abundantly but also a threat to the environment. It is a good additive for composite materials, which turns industrial-waste into industrial-wealth. The present study’s hypothesis is the utilization of waste materials into raw materials that solves storage and reduces material cost will favor industrial sectors. The current work examines the tribology using pin-on-disc apparatus by varying applied loads, sliding speeds with sliding distances. Wear debris, and worn surfaces have been analyzed to predict material behavior. The results reveal that superior wear resistance is achieved in AZ91D/7.5% (SiO2–HA) hybrid composite compare with other composites.

Zinc Oxide Nanostructure Synthesis on Si(100) by Vapor Phase Transport and the Effect of Antimony Doping on Photoelectric Properties, Morphology, and Structure

ABSTRACTZinc Oxide (ZnO) has been shown to exhibit semiconducting and piezoelectric dual properties. This has led to a large commercial demand on ZnO for optoelectronics that operate at the blue-ultraviolet regions. Consequently, varying techniques have been devised to create different nanostructures of ZnO. Here, the single step synthesis of ZnO nanostructures was performed on Si(100) substrates with a thin ZnO seed-layer. A modified chemical vapor deposition (CVD) method was developed to accomplish the structure formation. Sb doping of the structures in the gas phase was performed to study its effects on structure and optoelectronic properties. Different structures were realized including nanofilaments, nanoparticles, microflowers, nanorods, nanotubes, and nanocolumns. Only nanorods/columns, and nanotubes are shown in this work. Morphology was examined using scanning electron microscopy (SEM). Energy-dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRD) were used for structural studies. Optoelectronic properties were explored using room-temperature photoluminescence (PL) spectroscopy. PL data show the relative decrease in the number of defects and increase in crystal quality upon increasing reaction time. Significant structural effects were also observed upon doping. Some structural defects might be attributed to the diffusion of Sb ions into the lattices of ZnO, replacement of Zn by Sb, and ionic radii difference. These stacking faults are most likely the reason behind the dominance and broadening of DLE peak.