Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ2Comparative Microstructural, Mechanical, and Tribological Evaluation of Cu Matrix Composites Reinforced with B4C, B, Cr, Co, Al2O3, and Graphite via Powder Metallurgy
Macit, Cevher Kursat; Gürgenç, Turan; Aksakal, Bunyamin; Aslan, Naim
Copper and its alloys are widely used in electrical, automotive, aerospace, and energy applications because of their excellent thermal and electrical conductivity. However, the low hardness and poor wear resistance of pure Cu limit its use under tribologically demanding sliding conditions. In this study, Cu matrix composites reinforced with 1 wt.% boron carbide (B4C), boron (B), chromium (Cr), cobalt (Co), alumina (Al2O3), and graphite (Gr) were fabricated by powder metallurgy and comparatively evaluated under identical processing and testing conditions. Phase constitution and microstructural characteristics were analyzed by XRD, SEM, and EDS, while mechanical and tribological behavior was assessed by Vickers hardness and dry sliding wear tests. All reinforcements improved the hardness of the Cu matrix compared with unreinforced Cu. The hardness increase followed the order Cu–B4C (68.91%) > Cu–B (66.43%) > Cu–Gr (63.97%) > Cu–Al2O3 (61.79%) > Cu–Cr (42.69%) > Cu–Co (36.04%). Dry sliding wear tests, performed under a 10 N normal load, 0.05 m s−1 sliding speed, and 1000 m sliding distance against a 316L stainless-steel ball, showed that all reinforced composites exhibited lower mass loss and more stable sliding behavior than pure Cu. Among all samples, Cu–B4C displayed the best wear performance, with a 154.8% improvement in wear resistance relative to pure Cu. SEM analysis of the worn surfaces revealed that reinforcement addition reduced severe plastic deformation, groove formation, and delamination, leading to a more stable wear regime. Graphite- and boron-containing composites benefited from interfacial lubrication and contact stabilization, whereas B4C and Al2O3 improved wear resistance through rigid-particle strengthening and enhanced load-bearing capacity. By comparing ceramic, metalloid, metallic, oxide, and solid-lubricating reinforcements at the same low addition level and under identical processing and testing conditions, this study provides a reinforcement-selection framework for Cu-based composites requiring improved hardness and dry-sliding durability.
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İncele - MakaleAçık Erişim2026Scopus SJRQ2Multi-functional GeAg- and TiO2-modified diamond-like carbon thin film device: structure, surface properties, photoresponse, photosensitivity, and biological performance
Aslan, Naim; Şükrü Kurt, Mustafa; Mehmet Koç, Mümin; Yilmazer, Yasemin; Coskun, Burhan; Aksakal, Bünyamin
DLC films represent a promising class of materials that can be used in various applications due to their optical, optoelectronic, tribological, and biomedical characteristics. In this work, GeAg- and TiO2-modified DLC thin films were prepared using the magnetron sputtering method under ultrahigh vacuum conditions. DLC thin film characteristics and addition of GeAg and TiO2 into the DLC structure were confirmed and subsequently assessed via scanning electron microscopy (SEM), atomic force microscopy, energy dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and Raman spectroscopy. DLC thin film thicknesses were determined via SEM and found to be 235 nm and 380 nm for DLC/TiO2 and DLC/GeAg thin films, respectively. Contact angle and surface wettability analyses were performed for uncoated glass, GeAg- and TiO2-modified DLC thin films. The antibacterial properties of the DLC films were assessed for E. coli and S. aureus. The biocompatibility of these same films was confirmed using the L929 cell line, where no toxic effect was evidenced. To elucidate the optical characteristics of the thin films, a UV–vis spectrum was obtained, and band gap energies were proposed using these data. Photoresponse characteristics of the DLC thin films were assessed under varying illumination using current–time plots. It could be seen that DLC thin films’ responsiveness to light was dependent on illumination intensity. The results demonstrate that nanostructures are good candidates for multifunctional applications exhibiting good antibacterial and photoresponsive characteristics with outstanding biocompatibility.
- MakaleAçık Erişim2026Scopus SJRQ2Thickness- and Binder-Chemistry-Dependent Structural, Mechanical, and Tribological Performance of HVOF-Sprayed WC-Co and WC-Co-Cr Coatings on High-Speed Steel
Macit, Cevher Kursat; Aksakal, Bünyamin; Ayık, Merve; Gürgenç, Turan; Aslan, Naim
High-velocity oxy-fuel (HVOF) spraying was used to deposit WC-Co and WC-Co-Cr coatings on high-speed steel in order to determine how binder chemistry and coating thickness jointly control load support, friction, and dry sliding wear resistance. Nominal 50 and 100 µm coatings were compared within the same substrate framework by XRD, FT-IR, SEM/EDX, cross-sectional image analysis, Vickers hardness testing, dry sliding wear testing, and post-wear SEM/EDX. The coatings retained WC as the dominant crystalline phase, while weak overlapping features were associated with binder-rich regions and limited decarburization products. Cross-sectional observations confirmed continuous coating build-up close to the nominal thicknesses and low apparent dark-feature/porosity fractions. All WC-based coatings increased the effective hardness and reduced mass loss relative to uncoated HSS. Among the tested conditions, WC-Co-Cr-100 provided the highest effective hardness and the lowest mass loss after 1000 m sliding, whereas WC-Co-100 produced the lowest mean coefficient of friction. The results show that low friction and high wear resistance are not governed by identical mechanisms: WC-Co favours interfacial shear reduction, while the thicker Cr-containing coating provides superior resistance to material removal through improved carbide retention, binder stability, and coating-scale load support.
- MakaleYayıncıda açık erişim2026Scopus SJRQ3Interfacial Polarization in PS/Sm2O3 Nanocomposite Films for Low-Loss Frequency-Dependent Dielectric Application
Güner, Melek; Özkan, Betül Çiçek; Gürgenç, Ezgi; Macit, Cevher Kürşat; Aslan, Naim; Gurgenc, Turan
Rare-earth oxide nanoparticles offer a strategy to tune dielectric films via interfacial polarization while maintaining low-loss insulating behavior. Here, polystyrene/samarium oxide (PS/Sm2O3) nanocomposite films containing 0, 1, 3, 5, and 10 wt.% Sm2O3 were fabricated by solvent casting and evaluated as a low-loss dielectric for frequency-sensitive electronic applications. FTIR, XRD, SEM/EDX, and XPS confirmed successful Sm2O3 incorporation, preservation of the PS structure, formation of PS/Sm2O3 interfacial regions, and Sm3+/Sm–O species. XRD revealed amorphous PS with increasingly intense crystalline Sm2O3 reflections, whereas SEM/EDX showed relatively uniform filler distribution at low and moderate loadings and partial agglomeration at 10 wt.%. Dielectric spectroscopy at room temperature from 1 kHz to 1 MHz showed a frequency-dependent response governed by interfacial polarization and limited charge transport. At 1 kHz, the dielectric constant increased from 8.67241 ± 0.00280 for pure PS to 10.13061 ± 0.00641 for PS-10, while the loss tangent remained low (∼ 0.068). The dielectric loss increased moderately from 0.59535 ± 0.00236–0.69194 ± 0.00710, and AC conductivity rose from (3.31202 ± 0.01314) × 10−10 to (3.84935 ± 0.03948) × 10−10 S cm−1. These results indicate interface-controlled dielectric enhancement without conductive percolation, highlighting PS/Sm2O3 films for capacitor dielectric layers, insulating films, flexible electronics, and frequency-sensitive dielectric technologies.
- MakaleYalnız künye2025Scopus SJRQ2Green synthesis of environmentally friendly Ag/AgCl nanoparticles for use as solid phase extraction materials
Kurnaz Yetim, Nurdan; Hasanoğlu Özkan, Elvan; Aslan, Naim; Koç, Mümin Mehmet; Nartop, Dilek; Özcan, Cemile
Green synthesis is a prominent procedure used to easily and environmentally friendly fabricate nanostructures and nanoparticles (NPs), without complex instrumentation, intricate procedures, and harmful chemicals. This study investigated the green synthesis of silver NPs (AgNPs), with Aronia melanocarpa fruit extract as the reducing agent. Following synthesis optimization, AgNPs were characterized using a range of analytical techniques, including UV–Vis, XRD, SEM-EDX, BET, and TEM analyses. Based on the characterization results, an Ag/AgCl hybrid structure was formed. The Ag/AgCl NPs obtained were utilized as adsorbents to remove Cd(II) and Pb(II) heavy metals. The experimental factors that were optimized included pH (5.5), sample volume (5 mL), eluent type and concentration (2 M HNO3), adsorbent amount (5 mg), and extraction time (30 min). Under optimized conditions, the limits of detection were determined to be 9.6 and 4.8 µg/L for Pb(II) and Cd(II), respectively. These limits were established within a concentration range of 50–3,000 µg/L.
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İncele - MakaleAçık Erişim2025Scopus SJRQ1Y2O3-Doped BioGlass Coatings for Ti-6Al-4V Alloy: Insights into Degradation, Bioactivity, Ion Release, Adhesion, and Corrosion Behavior
Say, Yakup; Aslan, Naim; Cihangir, Salih; Murat, Oğuzkağan; Çaydaş, Ulaş
The Ti-6Al-4V alloy is particularly favored for orthopedic applications. However, important issues such as corrosion resistance, biocompatibility, and ion release need to be addressed. Therefore, this study aims to enhance the corrosion resistance and biocompatibility and reduce the ion release of the Ti-6Al-4V alloy by applying Y2O3-doped bioglass bioceramic coatings. The coatings were synthesized using the sol-gel method, including pure BioGlass and BioGlass with 1, 5, and 10 wt pct Y2O3. These coatings were then evaluated for their corrosion resistance, adhesion strength, degradation behavior, bioactivity, and ion release. The results showed that all coatings exhibited homogeneous, crack-free, and porous morphologies, which are favorable for osteointegration. The addition of 10 wt pct Y2O3 to the BioGlass coating resulted in a 52 pct increment in adhesion strength, which increased from 13.72 ± 2.80 MPa for single BioGlass coatings to 20.81 ± 2.53 MPa. All samples showed degradation values lower than 1 wt pct. Single BioGlass coatings significantly enhanced the bioactivity of Ti-6Al-4V alloy. However, the addition of Y2O3 negatively impacted BioGlass bioactivity, leading to a noticeable decrease as the Y2O3 content increased. Conversely, the presence of Y2O3 negatively impacted bioactivity and corrosion resistance while increasing the release of Ti ions. Specifically, the release of Ti ions increased from 79.5 ± 0.8 ppb in uncoated samples to 253.7 ± 15.3 ppb in BG-coated samples. For 1, 5, and 10 pct Y2O3-added samples, Ti releases were measured as 192.2 ± 33.6 ppb, 168.5 ± 62.4 ppb, and 194.3 ± 54.4 ppb, respectively. This research highlights the potential of tailored BioGlass coatings to improve the performance of Ti-6Al-4V alloys in orthopedic implant applications, particularly for enhancing bone integration and reducing implant failure.
AtıfScopus4WoS3OpenAlex5İncele - Kitap BölümüYalnız künye2025DLC coatings for optical and optoelectronic applications
Koç, Mümin Mehmet; Aslan, Naim
Diamond-like carbon (DLC) materials, special amorphous forms of carbon, are quite stable and durable, therefore finding applications in different industries. It baffles people from both industrial and scientific communities where tribological, mechanical, chemical, optical, and optoelectronic properties were used for various applications. DLC films were used in different optical applications regarding their optical performance. Having outstanding shear and mechanical performance and high chemical inertness makes DLC thin films a suitable candidate for optical applications and devices that work under tough conditions. Thus, they were preferred in photovoltaic devices, monitors, cameras, lenses, medical devices, fiber optic cable technologies, and illumination technologies. Their absorption, emission, and transmission characteristics were also addressed in various optical applications and studies.
AtıfScopus4OpenAlex1İncele - MakaleAçık Erişim2025Scopus SJRQ2Effects of ZrN and DLC coatings on morphostructural, corrosion, cell viability, and antibacterial properties of Ti6Al4V scaffolds
Aslan, Naim; Aksakal, Bünyamin; Cihangir, Salih; Fidan, Ferzan; Yilmazer, Yasemin
Lightweight and functional metallic materials are consistently favored and attract significant attention in the biomedical field. This study investigates the influence of ZrN and DLC coatings on Ti6Al4V scaffolds with varying porosities (40%, 50%, 60%) for biomedical applications. PVD-deposited coatings exhibited distinct growth mechanisms: High-resolution SEM-FIB analyses revealed columnar ZrN structures due to limited adatom mobility, while DLC formed conformal, amorphous layers via high-energy carbon species. Corrosion resistance decreased in 40% porous DLC and 60% porous ZrN-coated samples, likely due to coating defects and increased electrolyte access through open pores. ZrN coatings showed superior antibacterial activity and attributed to surface reactivity and potential ion release. In contrast, the uncoated 60% porous scaffolds demonstrated highest cell viability, suggesting that excessive coating on highly porous structures may hinder cell–material interactions. Furthermore, the cytotoxicity evaluations indicated that uncoated scaffolds exhibited the highest cell viability (77.51%) at 60% porosity after 48 hours, with ZrN coatings demonstrating better efficacy compared to DLC in the 50% and 60% porosity groups.
AtıfScopus3WoS3OpenAlex3İncele - MakaleAçık Erişim2024Effects of Porosity and Boron Reinforcement in AISI 316L Stainless Steel for Biomedical Applications
Aslan, Naim; Aksakal, Bunyamin; Fidan, Ferzan
AISI 316L stainless steel (SS) is one of the most widely used biomaterials in the manufacture of implants and biomaterials. It has advantages over equivalent biomaterials such as low cost, good mechanical properties and biocompatibility. The pores found in porous biomaterials provide mechanical interlock, ensuring strong attachment of the implant to the tissue. In this study, 20%, 30% and 40% by volume of polyvinyl alcohol (PVA) and Boron powder were added into 316L powder to obtain porous SS implant. To investigate the effect of porosity and boron effect on the stainless-steel implant material, the samples produced in PVA and Boron added groups, were sintered at 1180 oC under an argon atmosphere. With the evaporation of PVA in the structure, porous and boron added samples were obtained in two groups. Finally, the samples were subjected to Brinell hardness and compression tests and analyzed by SEM, EDS and XRD. As a result of the hardness tests, the highest values were measured as 37.006, 31.32, 25.28 HB. 39.5, 34.5, 26.2 MPa strengths were measured for 20%, 30% and 40% porous samples respectively.
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İncele - MakaleYalnız künye2024Scopus SJRQ2Sonochemical removal of Pb (II) ions from the water medium using Bi2S3 nanostructres
Kurnaz Yetim, Nurdan; Berberoğlu, Elif Aybike; Aslan, Naim; Koç, Mümin Mehmet; Özcan, Cemile
Removal of heavy metals becomes increasingly crucial for public health and the environment. In this regard, Bi2S3 nanoflowers were produced for heavy metal ion removal applications. Nanoflowers are fabricated using hydrothermal synthesis, and then tested as adsorbents for the removal of lead (Pb2+) ions from aqueous systems. To assess the morphological and chemical characteristics, Bi2S3 nanoflowers were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) techniques. Flame atomic adsorption spectroscopy (FAAS) was used in the assessment of heavy metal ion recovery. To determine the optimum conditions of the adsorption system, the effect of different parameters such as pH, eluent type and amount, adsorbent dose, adsorbent time, etc. were investigated. For lead removal, the optimum pH value was determined as 5.0, eluent dose and type were found 1 M HNO3. For 20 mL, the optimum adsorbent dose and time were found 50.0 mg, and 30 min, respectively. The adsorption capacity of the Bi2S3 nanoflowers was found to be quite higher than the results reported in similar works. It was illustrated that Bi2S3 nanoflowers have great potential to be used in water remediation applications as sorbent material.
AtıfScopus4WoS5OpenAlex5İncele - MakaleAçık Erişim2024Scopus SJRQ2Photodetector performance analysis of a hybrid MnPc/DLC device with high photoresponsivity, sensitivity, and On/Off ratio
Unal, Fatih; Aktas, Sitki; Kurt, Mustafa Sukru; Koc, Mumin Mehmet; Coskun, Burhan; Aslan, Naim; Arslan, Tayfun; Gur, Mahmut
The fabrication and characterization of high-performance devices for optoelectronic applications, particularly their response to incident light, are crucial. In this study, a MnPc/DLC device was fabricated using thermal evaporation and magnetron sputtering techniques, and its fundamental optoelectronic properties were characterised. Key diode parameters including barrier height, ideality factor, reverse saturation current, series resistance, and shunt resistance were determined using several methods, such as TE, Ohm's Law, the modified Norde method, and the Mikhelashvili method. The results from these methods were found to be consistent with varying light intensities. Additionally, photodetector parameters of the MnPc/DLC device were measured at ±1 V under light intensities of 20, 40, 60, 80, and 100 mW/cm2, and the findings were compared with the literature. The maximum values for photocurrent, photoresponsivity, photosensitivity, specific detectivity, and on/off ratio were 6.41 × 10−2 A, 2.49 A/W, 2.02 × 105, 5.8 × 109 Jones and 2.06 × 103, respectively. Notably, the photocurrent, photoresponsivity, photosensitivity, and on/off ratio values were found to be significantly higher and more promising compared to those reported in the literature.
AtıfScopus4OpenAlex4İncele - Kitap BölümüAçık Erişim2023Production technique–structure relationship in bioceramic-coated scaffold applications
Aslan, Naim; Topuz, Mehmet; Aksakal, Bunyamin; Dikici, Burak
It is well known that the surface of metal-based implants is very resistive in aggressive body environments due to the noble oxide layer naturally formed on their surfaces. However, their osseointegration properties are very low. By the way, specific cells attached are desired on the implant surface when the surface of an implant connects with tissue in many circumstances. Thus in parallel with technological developments, biomedical engineering focuses on the growth of new tissue on the implant surface or in the porosities of the implant. The bulk properties of metallic scaffolds, especially Young’s modulus, can be controlled by the porosity ratio of the scaffold but cannot form a bond between the implant and tissue interfaces. Thus the coating of scaffold walls with a bioactive material is required. In this chapter, bioceramic coating techniques of scaffolds, mechanical and corrosion behavior, biocompatibility, and interactions of surface/tissue interface, especially considering the last published reports, were reviewed, in detail.
AtıfScopus4OpenAlex4İncele - MakaleAçık Erişim2023Scopus SJRQ2Surface Morphology, Structural, Photovoltaic and Optoelectronic Properties of Diamond Like Carbon-Copper Nanostructures
Kara, Salih; Aslan, Naim; Kurt, Mustafa Şükrü
In this work, we produced Cu doped diomond like carbon films using the magnetron sputtering technique and assessed their structural electrical and optoelectronic characteristics. In the atomic force microscopy (AFM) measurements, it was observed that the surface of the Cu-DLC nanocomposite films was in a granular form and the presence of cluster-like formations. D and G bands, which are the characteristic peaks of the DLC structure, were observed in the Raman spectrum, while Cu and C peaks were observed in the energy dispersive (EDX) spectrum. Photocurrent, photocapacitance, photosensitivity and photoresponse values increased depending on the increasing light intensity. However, the Cu-DLC/n-Si structure displayed low photovoltaic properties. The capacitance and conductance values were considerably affected by the increase in AC signal frequency. The series resistance and the density of the interface states exhibited low frequency dependent behavior which were obtained using the electrical characteristics of the nanocomposite films.
AtıfScopus7WoS7OpenAlex6İncele - BildiriYalnız künye2023Investigation of corrosion behavior of ZrN-based PVD coatings on Ti-29Nb-13Ta-4.6Zr alloy in Hank's solution
Ali, Leila Ait; Aslan, Naim; Yilmazer, Hakan; Niinomi, Mitsuo; Sen, Anil; Dikici, Burak; Benhala, B.; Raihani, A.; Mansouri, K.; Qbadou, M.
In this study, the TiNbTaZr (TNTZ) alloys, which do not contain toxic and allergic elements, have been coated with hard ZrN physical vapor deposition (PVD) coatings to increase their in-vitro corrosion resistance. In-vitro electrochemical behavior of the ZrN coating and uncoated TNTZ alloy was evaluated using open circuit potential (OCP) and potentiodynamic polarization (PDS) techniques, respectively. The characterizations of the coatings were carried out using scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD). The SEM examinations showed that ZrN coating is homogeneous. Besides, ZrN coating had a higher corrosion resistance than uncoated TNTZ alloy in Hank's solution.
- MakaleAçık Erişim2023Scopus SJRQ3Morpho-structural and compressive mechanical properties of graphene oxide reinforced hydroxyapatite scaffolds for bone tissue applications
Fidan, Ferzan; Aslan, Naim; Koç, Mümin Mehmet
Hydroxyapatite (HA) is a unique material that has the potential to be used to replace bones and teeth in the field of orthopedics and dentistry since HA exhibits quite similar biological and chemical characteristics to human bone. Hydroxyapatite ceramics are bioactive materials used to repair damaged human tissue. The pores in the porous hydroxyapatite ceramics provide a mechanical interlock, enabling a solid bond and fixation between the implant and bone. In this study, 0.5wt%, 1wt%, and 1.5wt% graphene oxide (GO) reinforced porous HA structures were obtained using the space-holder method to increase the strength of hydroxyapatite with low mechanical strength. NaCl was used as a spacer, and PEG 400 as a binder. Scaffold structures with 40% porosity rates were sintered at 1000 °C under vacuum. Finally, a compression test was applied to the samples which were previously analyzed by SEM, EDS and XRD. The compressive strengths of 0.5%, 1%, and 1.5% graphene oxide reinforced porous HA samples were determined between 8.04 and 31.14 MPa. The highest compressive strength was recorded as 31.14 MPa in the 1% GO added sample, and the lowest compressive strength was recorded as 8.04 MPa in the 1.5% GO added sample. In addition, it was understood that the mechanical properties did not increase regularly with the increase of graphene oxide reinforcing.
AtıfScopus4OpenAlex3İncele - MakaleAçık Erişim2023Scopus SJRQ1FeCoNiMnCr high-entropy alloys (HEAs): Synthesis, structural, magnetic and nuclear radiation absorption properties
Şimşek, Telem; Kavaz, Esra; Güler, Ömer; Şimşek, Tuncay; Avar, Barış; Aslan, Naim; Almisned, Ghada; Zakaly, Hesham M.H.; Tekin, H.O.
We report the synthesis and structural, magnetic and Radiation shielding properties of High Entropy Alloy (HEA) produced through mechanical alloying method. Using an X-Ray Diffractometer (PanalyticalEmpryan) with CuK radiation at 45 kV and 40 mA, the phase identification starting elements and as-milled powders are identified. Scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX), morphological and microstructural investigations were conducted (FEI Quanta FEG 450). EDX and elemental mapping analyses are conducted to assess the purity and elemental distributions of the synthesized alloys. Using the Quantum Design Physical Characteristics Measurement System (PPMS) with vibrating sample magnetometer (VSM) and a magnetic field of 30 kOe at room temperature, magnetic properties are examined. Using 137Cs radioisotope and mathematical methods, gamma-ray and neutron shielding properties of HEA are investigated in a conventional transmission setup using experimental and theoretical approaches. In the presence of a 3 T applied field, the sample exhibits a low magnetization of 5.30 emu/g at 300 K. Moreover, Ms is raised to 22 emu/g at 10 K owing to decreased thermal effects. The temperature dependence of the magnetization is recorded in the presence of a 1 T applied field. HEA exhibits superior neutron attenuation properties than conventional absorption materials such as B4C, graphite, and water. Our results showed that the synthesized HEA has superiority over other alloys and conventional neutron absorption materials. It can be concluded that the proposed novel HEA might be investigated further in terms of broadening its characterization and clarifying its other crucial properties to extend the scope of the current investigation.
AtıfScopus42OpenAlex47İncele - MakaleYalnız künye2023Scopus SJRQ2Silver-Doped Diamond-Like Carbon (DLC:Ag) Nanocomposite Films for Solar Tracking Applications
Aslan, Naim; Kurt, Mustafa Şükrü; Koç, Mümin Mehmet
Diamond-like carbon (DLC) films are often investigated for their mechanical properties. In this report, we assessed the electrical and photovoltaic characteristics of DLC:Ag composite films produced for solar tracking and/or photodetector device purposes. We used the magnetron sputtering technique to prepare DLC:Ag thin films where DLC and Ag were co-deposited on Si wafers. Structural characterization of the thin films was performed using AFM, EDX, and Raman spectroscopy. Current–voltage, capacitance–voltage and conductance–voltage characterizations were employed to assess the electrical characteristics and photovoltaic characteristics of the DLC:Ag thin films. I–V characteristics were characterized under various illumination intensities to assess the effect of light intensity on the DLC:Ag composite films. We found that silver-doped DLC composite thin films are responsive to light and exhibit detector-like behaviour. Barrier height was found to be between 0.55 eV and 0.81 eV while the ideality factor was calculated to be between 1.94 and 7.11. It was found that photovoltaic and diode properties were affected by applied illumination intensities. C–V characteristics indicated that the electrical properties of the thin films are responsive to the signal frequency. The density of interface states was calculated which was thought to be a factor related to this behaviour.
AtıfScopus17WoS16OpenAlex14İncele - MakaleAçık Erişim2023Scopus SJRQ2ZrN and ta-C coatings on titanium for biomedical applications: Improved adhesion, corrosion, antibacterial activity, and cytotoxicity properties
Aslan, Naim; Aksakal, Bünyamin; Cihangir, Salih; Cetin, Fadime; Yilmazer, Yasemin
Commercially pure titanium (CP-Ti) is extensively used in biomedical applications. However, numerous qualities, including mechanical strength, corrosion resistance, and wear resistance, must be established for long-term performance as an implant material. This study investigates the enhancement of surface properties of CP-Ti through physical vapor deposition (PVD) with ZrN and ta-C (tetrahedral amorphous carbon). Among the coatings, ZrN revealed best overall results, such as adhesion, corrosion, microhardness, and wettability, excluding cell viability when compared to ta-C. E. coli and S. aureus were employed for antibacterial activity and MTS cell viability experiments. Compared to α-titanium, hardness tests revealed 91% increase in ZrN coating, and %22 increase in ta-C coating. Super-hydrophobicity and excellent antibacterial activity were found for ZrN coatings in comparison to ta-C. These findings emphasize the potential of ZrN and ta-C coatings to improve the surface properties of titanium, encouraging it to be used in biomedical devices. Graphical abstract: [Figure not available: see fulltext.].
AtıfScopus16WoS16OpenAlex19İncele - MakaleAçık Erişim2023Scopus SJRQ2Investigation of fundamental electrical and optoelectronic properties of an organic- and carbon-based MnPc/GC photodiode with high photosensitivity
Aktas, Sitki; Unal, Fatih; Kurt, Mustafa Sukru; Koç, Mümin Mehmet; Arslan, Tayfun; Aslan, Naim; Coşkun, Burhan
The aim of this work is to provide an alternative to optoelectronic devices that use carbon and organic materials. To achieve this, we coated a modified MnPc organic semiconductor compound onto a graphite-like carbon (GC) thin film using the thermal evaporation technique, and fabricated an organic-based, highly light-sensitive MnPc/GC hybrid heterojunction. The heterojunction had a transmittance of approximately 60% in the visible region, an absorption coefficient of ∼106 m−1, and an energy band gap of 2.6 eV. Subsequently, Ag contacts were grown on the surface of each layer, and the Ag/MnPc/GC/Ag photodiode was subjected to fundamental electrical analysis at various light intensities and a ±3 V applied potential. Analysis in a dark environment revealed that the photodiode had a rectification ratio of 2.59 × 103, a series resistance of 28 Ω, and a shunt resistance of 4.17 × 104 Ω, as calculated from Ohm’s law. The diode ideality factor and barrier height of the photodiode were determined from thermionic emission theory to be 5.60 and 0.71 eV, respectively, and it was observed that these decreased with increasing light intensity. The photodetector parameters of the MnPc/GC hybrid photodiode were determined under positive and negative applied potentials at various light intensities. The highest photocurrent, photoconductive responsivity, photosensitivity, and specific detectivity were determined to be 1.512 × 10−1 A, 11.52 A.W−1, 9.83 × 105, and 2.48 × 1012 Jones, respectively, which were significantly higher than those reported in literature for organic and inorganic-based photodiodes. Based on the findings, it was concluded that the Ag/MnPc/GC/Ag photodiode holds promise as an alternative for sensors, solar cells, photodetectors, and optoelectronic communications applications.
AtıfScopus10WoS9OpenAlex14İncele - MakaleAçık Erişim2022Hidrotermal yöntem kullanılarak ZnO@Fe3O4 kompozit nanoyapıların sentezi ve karakterizasyonu
Aslan, Naim
Buçalışmada,ZnO@Fe3O4kompozitnanoyapılarhidrotermalyöntemkullanılarak sentezlenmiştir.Farklıoranlarda Fe3O4katkısıylaeldeedilennanoyapılarınyapısal karakterizasyonuiçinX-ışınıkırınımanalizigerçekleştirildiveherhangibirsafsızlıkpikine rastlanmadı. Morfolojik görüntülemede taramalı elektron mikroskobu (SEM) ve geçirimli elektron mikroskobu (TEM) kullanıldı.Nanoyapılarınmorfolojisinde Fe3O4etrafındaZnOnano taneciklerinindekoreedildiğianlaşılmıştır.ElementalanalizdeiseFe,ZnveOpikleri kaydedilmiştir. ZnO@Fe3O4nanokompozit yapıların bant aralığı enerjileri Uv-Vis spektromotresi aracığılıyla elde edilen absorbans datalarından elde edilmiştir. Nanoyapıların bant gap değerleri yaklaşıkolarak2-2.1eVaralığındahesaplanmıştır.ManyetiközellikleriseVibratingSample Magnetometer (VSM) kullanılarak tespit edildi ve Fe3O4katkı oranına bağlı olarak 3.76 emu/g ile 7.96 emu/g değerleri bulundu. Bu değerler sınırlı bir ferromanyetik özellik göstermesine rağmen ZnO’nun sahip olduğu gelişmiş optik, elektronik özelliklerinden dolayı optoelektronik ve medikal görüntüleme uygulamalarında önem arz etmektedir.
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