Showing 698 results for Type of Study: Research Paper
Payam Tayebi, Ramin Hashemi,
Volume 22, Issue 1 (3-2025)
Abstract
This study presents the manufacturing of Al 1050/Mg AZ31B bimetallic sheets using the cool roll bonding process, followed by an investigation of the effect of annealing temperature on mechanical properties and microstructural features. Annealing treatment was performed at 200, 300, and 400 degrees Celsius. Mechanical testing includes tension, micro-hardness, three-point bending, and fracture toughness. Scanning electron microscopy equipped with energy-dispersive X-Ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD) were used to investigate the microstructure in the infiltration zone. Mechanical testing shows that increasing the annealing temperature decreases the tensile strength of the two-layer specimens. Micro-hardness, XRD, and SEM-EDX investigations confirm the presence of intermetallic particles in the penetration zone. The Micro- hardness test showed that with the increase of the annealing temperature, the hardness in the penetration zone of Al 1050/Mg AZ31B increases. This increase in micro-hardness result confirms the presence of harder intermetallic phases with increasing annealing temperature in the penetration zone.
Zeinab Abbasali Karajabad, Adrine Malek Khachatourian, Mohammad Golmohammad, Ali Nemati,
Volume 22, Issue 1 (3-2025)
Abstract
Hybrid asymmetric supercapacitors using distinct cathode/anode materials offer enhanced energy density by expanding operational potential windows compared to symmetric configurations. In this work rGO/α-Fe₂O₃ and rGO/TiO₂ nanocomposites were synthesized via hydrothermal method for hybrid asymmetric supercapacitors applications. Field emission scanning electron microscope (FESEM) revealed uniform distribution of spherical α-Fe₂O₃ and TiO₂ nanoparticles on rGO sheets. The X-ray diffractometry (XRD) analysis confirmed the presence of the hematite and anatase in the rGO/α-Fe2O3 and rGO/TiO2 nanocomposites, respectively. Additionally, in the XRD spectra of both nanocomposites, a broad peak corresponding to the (002) crystalline planes of rGO was observed. Electrochemical testing showed specific capacities of 130 F/g (rGO/α-Fe₂O₃) and 253 F/g (rGO/TiO₂) at 5 mV/s in 1M KOH. The assembled hybrid asymmetric supercapacitors (rGO/α-Fe₂O₃//rGO/TiO₂) achieved a 1.6 V operational potential window. Power density and energy density of 1066 W kg-1 and 9.7 Wh kg-1 were achieved at a current density of 1 A/g, respectively.
Adil Kadum Shakir, Ebrahim Ghanbari-Adivi, Aref S. Baron Baron, Morteza Soltani,
Volume 22, Issue 1 (3-2025)
Abstract
Nanomaterials have significantly transformed multiple scientific and technological fields due to their exceptional properties, which result from their quantum confinement effects and high surface-to-volume ratios. Among these materials, zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles have attracted considerable interest because of their diverse applications.
In this study, TiO2-ZnO nanocomposites were synthesized using varying calcination times of 1, 1.5, 2, 2.5, and 3 hours. Characterization of fabricated samples through X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDXS) confirmed the successful fabrication of the nanocomposites. In this regard, XRD analysis revealed anatase TiO2 and hexagonal wurtzite ZnO phases. Raman spectroscopy also supported these findings, identifying characteristic peaks of both TiO2 and ZnO.
The calcination time had a minimal effect on the crystal structures and also morphology of the nanocomposites, which gave rise to its negligible impact on optical properties and biological activities of the samples. Optical properties assessed by means of UV-visible and photoluminescence (PL) spectroscopy showed consistent band gap absorption and emission profiles across all samples, among which the nanocomposite calcined for 1 hour exhibited the best optical properties.
The sample prepared at 1 hour not only showed the most favorable optical properties, but also demonstrated significant antibacterial, antifungal, and cytotoxic activities, which make it suitable for various applications. In this regard, a reduction of more than 99.9% occurred in the number of Escherichia coli and Staphylococcus aureus bacteria and also Candida albicans fungus by using TiO2-ZnO nanocomposite. Besides, addition of 500 µg/ml of nanocomposite decreased the cell viability to 34.47%, which signifies its high cytotoxicity activity.
Amirreza Bali Chalandar, Amirreza Farnia, Hamidreza Najafi, Hamid Reza Jafarian,
Volume 22, Issue 1 (3-2025)
Abstract
This study investigates the microstructural evolution and variations in the mechanical properties of pre-cold worked Nimonic 80A superalloy, subjected to two levels of deformation (25% and 50%) and welded via Gas Tungsten Arc Welding (GTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) techniques using ER309L filler wire. The objective is to evaluate the effect of the initial microstructure on the welding behavior of Nimonic 80A and compare the weldments produced using GTAW and PCGTAW. Microstructural characterization was conducted using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). XRD analysis demonstrated that the welding pulsed current mode, compared to the continuous current mode and at equal heat input, led to a refined microstructure, suggesting improved welded mechanical properties of the weld. It also showed a potential reduction in grain refinement with a higher level of cold work. Tensile testing demonstrated that fractures consistently occurred within the weld zone (WZ), with the PCGTAW sample achieving the highest tensile strength (766 MPa). Microhardness analysis indicated a notable reduction in hardness within the heat-affected zone (HAZ) and WZ, particularly in the 50% pre-cold worked sample. However, PCGTAW retained higher hardness due to its refined microstructure. The weld metal primarily consisted of an austenitic microstructure characterized by dendrites and interdendritic precipitates. Microstructural analysis revealed that welding induced significant changes in the weldment, with the PCGTAW sample exhibiting a more uniform microstructure and smoother transitions at the weld interface. Fractography confirmed ductile fracture in all specimens, with smoother and more uniformly distributed dimples in the PCGTAW sample. These findings highlight the advantages of pulsed current welding in optimizing the mechanical performance of Nimonic 80A welds and suggest its potential application in industries requiring superior weld quality.
Mohammad Derakhshani, Saeed Rastegari, Ali Ghaffarinejad,
Volume 22, Issue 1 (3-2025)
Abstract
In this research, the morphology of the Ni-W coating was modified by adding graphene oxide (GO) nanosheets in such a way that a foam-like structure with high porosity and holes in the form of intertwined tunnels was obtained. Different amounts of GO nanosheets were added to the plating bath and the resulting coating was examined. In order to estimate the electrochemically active surface area, the cyclic voltammetry (CV) test was used. Moreover, the linear polarization test (LSV) and chronoamperometry in 1 M NaOH were conducted to investigate the electrocatalytic activity for the hydrogen evolution reaction (HER). It was found that by adding 0.4 g/L GO to the electroplating bath, the electrocatalytic properties are doubled and the active surface of the electrode is significantly increased.
Amin Rahiminejad, Mojgan Heydari, Fariba Tajabadi,
Volume 22, Issue 1 (3-2025)
Abstract
Targeted drug delivery systems have been developed to overcome the disadvantages of conventional drug delivery systems and folate is one of the targeting molecules that has received attention in recent years. The attachment of this molecule to the surface of niosomal carriers has been achieved using Castor oil as an intermediate molecule. We synthesized caster folate (CF) and incorporate to noisome structure as biocompatible component for targeted delivery of anticancer drug Doxorubicin. This research studies the novelty of castor folate ester in the scope of niosome-based drug delivery systems. The aim was to investigate the feasibility of manufacturing and evaluating a niosomal carrier containing the drug doxorubicin hydrochloride (DOX) and its targeting by the combination of CF. The results of Fourier Transform Infrared Spectroscopy (FTIR) confirm chemical bounding between folic acid and castor oil. SEM showed good morphology with spherical structure of niosomes. These niosomes have particles size of 330 to 538 nm for different samples. Also, zeta potential was -28 to -40 mV that results good stability. The addition of CF to niosomal samples increased wettability and drug loading efficacy and along with DLS and zeta potential results confirms the folate impact on surface hydrophilicity of niosome spheres. The prepared formulations increased the effectiveness of doxorubicin on L929 fibroblast cells. The proposed biocompatible component showed the role of CF in the architectural integrity of niosomal lipid bilayers.
Shatha Batros, Farqad Rasheed, Hussein Hussein,
Volume 22, Issue 1 (3-2025)
Abstract
The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.
The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.
Ahmed Kharmouche,
Volume 22, Issue 1 (3-2025)
Abstract
Series of cobalt (Co) thin films with various thicknesses ranging from 50 to 400 nm have been fabricated using thermal heating under vacuum. We explore the impact of the thickness layer on the structural and morphological properties of the films. X-Ray diffractions and atomic force microscopy tools have been used to carry out the structural and the morphological properties of these films. The films are principally c-axis oriented, polycrystalline and with <0001> texture. The crystallites sizes have been found to range from 18.40 to 79.46 nm, and they increase with increasing thickness. The ratio c/a value indicates that Co films are subject to a tensile stress, probably because of the way the film grows. The microstrain is positive and ranges from 1.53 to 3.56%. Atomic force microscopy observations indicate the formation of crystallites according to the Stranski-Krastanov mode. The films topographical surfaces are very smooth, the average root mean square roughness ranging from 0.2 to 1.5 nm.
Keywords: Co; Thin films; XRD; Crystallite size; AFM.
Sumrit Mopoung, Khachidapron Seeoon,
Volume 22, Issue 2 (6-2025)
Abstract
Activated carbon preparation from tamarind wood derived charcoal by microwave-assisted sodium chloride activation was studied to investigate the effects of 0-5 wt.% NaCl and 450-850 W microwave heating power. The properties of the derived products were analyzed by FTIR, XRD, SEM-EDS, and BET. Methylene blue adsorption by the activated carbon products was also studied to evaluate the contract time, pH, methylene blue concentration, and adsorption isotherms. The study’s results showed that the percent yields (77.42-92.52%) of the fabricated activated carbons decrease with increasing wt.% of NaCl and MP. On the other hand, the contents of disordered graphitic carbon, carbonate, basic surface functional groups, and mesopores increased. However, 3 wt.% NaCl and 600 W microwave irradiation power were identified as appropriate conditions for activation, which created the micro-mesopore (pore size range 1.59 -14.76 nm) on the surface of the derived activated carbon products. Optimal values of equilibrium time and pH for methylene blue adsorption are 60 minutes and 8, respectively. The results of methylene blue concentrations were fitted to the Langmuir isotherm indicating 33.33 mg/g as the maximum methylene blue adsorption capacity.
Manjunath Vatnalmath, Virupaxi Auradi, Bharath Vedashantha Murthy, Madeva Nagaral, Veeresh Kumar G B, Suresh Shetty, Suresh Shetty,
Volume 22, Issue 2 (6-2025)
Abstract
Dissimilar joints of AA2219 and Ti-6Al-4V alloys are obtained using the vacuum diffusion bonding method. The bonding pressure is controlled in the range of 1-4 MPa by keeping the bonding temperature and holding time constant. The influence of the bonding pressure on the microstructure and mechanical properties of the bonding joints is investigated. The diffusion behaviour across the interface of the bonding joints is increased with the increase in bonding pressure. The interface morphology of the specimen bonded at lower bonding pressures exhibits scraggly voids and cracks. The irregular voids and cracks are squeezed and gradually closed due to the significant increase in the diffusion between Al and Ti. The maximum shear strength of 81 MPa is obtained for the joint made at the bonding pressure of 4 MPa, and a diffusion layer of 0.76 µm is formed at the Ti side interface. The fracture morphology inferred the brittle failure of the bonding joints due to the formation of intermetallic compounds like TiAl, TiAl2, and TiAl3 at the interface of Al and Ti.
Uglal Pandit Shinde, Somnath Bhika Handge, Dharma Kisan Halwar,
Volume 22, Issue 2 (6-2025)
Abstract
This study investigates the effect of SnO2 as an additive on the structural, electrical, optical, and gas sensing properties of LaCrO3 nanoparticles. SnO2 is added into the LaCrO3 by weight percentage (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. %, 9 wt. % and 11 wt. %) employing screen printing method. Initially, the nanoparticles of SnO2 and LaCrO3 separately synthesis by sol-gel method and then used for the development of thick films. LaCrO3 is used as host material while SnO2 is additive material. The structural characterizations like FESEM, EDX and XRD were carried out to investigate the morphology, elements and crystallite size respectively. The inclusion of SnO2 modifies the crystalline structure and surface morphology of LaCrO3, as revealed by structural analyses. The optical characterizations like FTIR and UV were used for the study of impact of SnO2 additive on functional group and band gap of the host material respectively. Optical studies indicate a modification in the bandgap, affecting light absorption properties and indicating changes in electronic transitions. The electrical characterizations were conducted by using half bridge method. Electrical resistivity measurements show enhanced performance, likely due to variation in charge carrier mobility induced by the SnO2 additive. Among other selected wt. % SnO2 additives, 9 wt. % SnO2 added LaCrO3 thick films shows maximum sensitivity to CH4 gas at 120oC operating temperature. The gas sensing characteristics demonstrate enhanced sensitivity, selectivity, and response time to target gases, suggesting that SnO2 doping improves the sensing capabilities of LaCrO3 nanoparticles, making them more efficient as a gas sensor. Obtained findings suggest that, SnO2 as an additive enhances the multifunctional properties of LaCrO3 nanoparticles, making them promising candidates for advanced gas sensing applications.
Zainab Dhyaa Fawzy, Saja Ali Muhsin, Taha Hassan Abood,
Volume 22, Issue 2 (6-2025)
Abstract
Ceramics in dentistry have been mainly recommended from a cosmetic perspective. Yet, the hardness behaviour may limit the application in many cases. Although amber glass is used for medications and chemicals, no studies focus on using amber glass for dental purposes as an additive material. This study aims to investigate the dark amber glass behaviour as a new additive material for dental ceramics. The amber glass powder was prepared using the ball mill technique. For the amber glass powder characterization, the SEM/EDX, particle size, DSC, Ion release, and XRD analysis were tested compared to VITA Lumex® AC ceramic. In addition, the Vickers hardness test was applied for ceramic and ceramic amber with an addition of 0.01g, 0.03g, and 0.05g amber glass powder following the DIN EN ISO 6872/ 2019. Statistically, the ANOVA (post hoc- Tukey) test was used for hardness testing analysis at a significant P-value of (P≤0.05). The results show that the amber glass behaviour and composition elements seem similar to VITA ceramics. The addition of amber glass powder to ceramic shows an increase in the HV hardness of specimens. Overall, it was concluded that the amber glass powder could be a promising material for ceramics to use as an additive powder.
Ali Keramatian, Mohammad Hossein Enayati, Fatemehsadat Sayyedan, Sima Torkian,
Volume 22, Issue 2 (6-2025)
Abstract
The aim of this study was to investigate the effect of current density on the microstructure of electrodeposited Ni–WC–TiC composite coatings on 304 stainless steel and compare the corrosion resistance of the coating and substrate in a 3.5 wt.% sodium chloride solution. A Watts nickel bath was employed under direct current (DC) conditions. Microstructure, elemental composition, and phase composition analyses were conducted using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results revealed that the coating formed at a current density of 40 mA/cm² exhibited a denser microstructure with higher cohesion and uniformity compared to coatings produced at other current densities. The corrosion resistance of the coating and substrate was evaluated using Tafel and electrochemical impedance spectroscopy (EIS) analyses. The corrosion test results indicated that the substrate exhibited superior corrosion resistance compared to the coating. Based on the dynamic polarization test plots, the corrosion mechanism of the substrate is active-quasi passive, with a pseudo-passive layer forming on the sample which remains stable within the potential range of -0.17 to 0.17 V. Beyond this potential range, the sample becomes susceptible to pitting. In the coated sample, the corrosion behavior is similar to that of the substrate, with the exception that the pseudo-passive layer remains stable within a narrower potential range of -0.19 to 0.08 V.
Nur Aziah Suhada Naim, Muhammad Faiq Abdullah, Sung Ting Sam, Wan Ahmad Radi Wan Ahmad Yaakub,
Volume 22, Issue 2 (6-2025)
Abstract
Despite being an effective material for food packaging, chitosan (CS) exhibited poor ductility when processed into film, which restricted its use in this industry. In this study, composite films with enhanced properties were developed by incorporating polyvinyl alcohol (PVA) into CS through a simple solution casting method. The effects of different PVA/CS weight ratios (70:30, 50:50, and 30:70 w/w) on the morphology, mechanical properties, antibacterial activity, and soil degradation of the composite films were analyzed. Compared to the pristine PVA film, increasing the CS content in the PVA/CS composite film enhanced thickness, stiffness, roughness, antibacterial efficiency, and degradation rate, while reducing tensile strength and elongation at break. Fourier transform infrared (FTIR) spectroscopy revealed the highest intermolecular interactions in the PVA/CS composite film with 70:30 w/w. Antibacterial activity tests and soil burial analysis demonstrated that the PVA:70/CS:30 composite exhibited significantly higher antibacterial activity toward Escherichia coli and Bacillus subtilis bacteria as opposed to PVA film, along with a moderate degradation rate of 76.76% following 30 days soil burial, effectively balancing biodegradability and material integrity. These findings suggest that the PVA:70/CS:30 composite is a promising alternative for sustainable and functional biodegradable packaging solutions.
Mahdi Rajaee, Mahdi Raoufi, Zeinab Malekshahi Beiranvand, Abbas Naeimi,
Volume 22, Issue 2 (6-2025)
Abstract
This research explored the impact of the nickel-to-manganese ratio and the influence of the matrix phase on the properties of W-Ni-Mn tungsten heavy alloys (WHAs), aiming to determine the optimal composition for achieving desirable alloy properties. For this purpose, tungsten, nickel, and manganese powders with specified weight percentages underwent two rounds of wet milling. Powder mixtures were obtained with weight ratios of 90W-6Ni-4Mn, 90W-8Ni-2Mn, and 88W-10Ni-2Mn. These mixtures were then compressed through the cold pressing method at a pressure of 250 MPa. Subsequent reduction and sintering processes were carried out in a tube furnace at temperatures of 1150 and 1400 °C, respectively. Microstructural characterization was conducted using both optical and electron microscopy. The results showed that the change in chemical composition is not significantly effective on the sintering density of the samples and also the highest sintering density, reaching 90.11%, was achieved with the 88W-10Ni-2Mn sample. Furthermore, the results demonstrated that carburization of W-Ni-Mn WHAs during the sintering process led to an increase in the micro-hardness of the samples. The highest hardness, measuring 381 Hv, was observed in the 90W-6Ni-4Mn alloy, where carburization occurred. XRD results revealed that an increase in the nickel-to-manganese ratio led to a reduction in the peaks of manganese carbide and tungsten carbide. Consequently, this decrease in carbide peaks resulted in a reduction in hardness, reaching 352 Hv in the case of the 88W-10Ni-2Mn sample. Additionally, the alloys 90W-6Ni-4Mn and 88W-10Ni-2Mn both exhibited the lowest continuity, a value of 0.5. Fracture surface SEM images illustrated that the 90W-6Ni-4Mn alloy, characterized by the lowest nickel-to-manganese ratio (1.5), exhibited the highest trans-granular fracture mode involving cleavage and matrix tearing, which is considered desirable. Furthermore, an increase in the matrix phase content resulted in a shift of the preferred crack path, originating from the matrix phase.
Amin Rezaei Chekani, Malek Naderi, Reza Aliasgarian, Yousef Safaei-Naeini,
Volume 22, Issue 2 (6-2025)
Abstract
This paper presents the novel fabrication method of a three-dimensional orthogonally woven (3DW) C/C-SiC-ZrB2 composite and the effects of ZrB2 and SiC particles on microstructure and the ablation behavior of the C/C–SiC–ZrB2 composite are studied. C/C–SiC–ZrB2 composite was prepared by isothermal-chemical vapor infiltration (I-CVI), slurry infiltration (SI), and liquid silicon infiltration (LSI) combined process. Pyrolytic carbon (PyC) was first infused into the 3DW preform by I-CVI at 1050°C using CH4 as a precursor in order to form a C/C preform with porous media. The next step was graphitization at 2400°C for 1hr. Then ZrB2 was introduced into 3DW C/C preform with a void percentage of 48 by impregnating the mixture of ZrB2 and phenolic resin, followed by a pyrolysis step at 1050°C. A liquid Si alloy was infiltrated, at 1650 °C, into the 3DW C/C composites porous media containing the ZrB2 particles to form a SiC–ZrB2 matrix. An oxyacetylene torch flame was utilized to investigate The ablation behavior. ZrB2 particles, along with the SiC matrix situated between carbon fiber bundles, form a compact ZrO2-SiO2 layer. This layer acts as a barrier, restricting oxygen infiltration into the composite and reducing the erosion of carbon fibers. The findings were supported by FESEM imaging and further confirmed through x-ray diffraction and EDS analysis. The addition of ZrB2 to the C/C-SiC composite resulted in a lower mass and linear ablation rate; 2.20 mg/s and 1.4 µm/s respectively while those for C/C-SiC composite were 4.8 mg/s and 6.75 µm/s after ablation under an oxyacetylene flame (2500°C) for 120 s.
Ines Dhifallah, Faten Rhouma, Imen Saafi, Jamila Bennaceur, Wafa Selmi, Wissem Dimessi, Radhouane Chtourou,
Volume 22, Issue 2 (6-2025)
Abstract
In this study, a novel three-step method for the synthesis of ZnO and branched ZnO microrods was developed. Numerous techniques were used to analyze the obtained samples: photoluminescence (PL) spectroscopy, raman spectroscopy, fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-rays (EDX), ultraviolet-visible spectroscopy (UV-visible) and X-ray diffraction (XRD). The XRD study and Rietveld refinement confirmed that the synthesized samples have the hexagonal wurtzite structure of ZnO without any impurity with the P63mc space group. To further verify our experimental results, structural parameters were calculated by First Principles Density Functional Theory (DFT) calculations and compared with experimental ones. A small decrease in the unit cell volume following the branching process was observed by the DFT calculations and Rietveld refinement results. Raman spectra showed peaks corresponding to the phonon modes of hexagonal wurtzite ZnO, which was consistent with the results of XRD and Rietveld refinement. SEM confirmed that ZnO and BZnO samples have hexagonal rod and branched rod shapes. BZnO showed stronger green PL emission but lower overall PL intensity compared to ZnO. The reduced photoluminescence (PL) intensity across all frequencies indicates enhanced separation of the photogenerated electron-hole pairs in branched ZnO (BZnO) due to decreased recombination.
Noor Alhuda Hassan, Zainab Jaf, Hanaa Ibrahem, Mohammed Hamid, Hussein Miran,
Volume 22, Issue 2 (6-2025)
Abstract
This work reports the influence of Cu dopant and annealing temperature on CdOx thin films deposited on glass substrates by spray-pyrolysis method. The Cu doping concentrations were 0, 0.46, and 1.51 at% with respect to the CdOx undoped material. Then, the fabricated films were subjected to annealing process at temperature of 450°C. X-ray diffraction (XRD) examination confirms that the as-deposited films show a cubic crystallographic structure with high purity of CdO in the annealed films. It was found that the (111) peak is the most predominant diffraction orientation in the surveyed samples. At the microscopic scale, AFM machine was operated to quantify the three important parameters of the mean roughness (Ra), rms value (Rq), and z scale. These parameters hold highest values for the sample with 0.46 at% of Cu. Finally, reflectance, absorbance, transmittance and other optical parameters dielectric measurements were comprehensively analyzed. Our evaluation of optical band gaps for the studied samples reveals that the synthesized films have direct band gap character with the fact that the rise in the Cu contents in the as-deposited films lead to lessen the band gap values. In contrast, annealing process results in raising the band gap.
