Papers by Keyword: Atomic Force Microscopy

Abstract: The structural changes of a type of polydiacetylene single crystal obtained via the physical vapor transport technique induced by the formation of polymeric backbone chains upon ultraviolet irradiation are discussed in this paper. On the basis of the results of X-ray diffractometry, X-ray topography, and atomic force microscopy, the structural changes were confirmed to be due to the formation of backbone chains along the basal (010) plane. The high periodicity between equivalent (010) planes is maintained regardless of the formation of backbone chains. The observation of the surface morphology on the basal (010) plane revealed that many polymeric bundles were formed in both the [001] and [101] directions.

Abstract: Lithium metal batteries (LMBs) are promising candidates for next-generation energy storage devices because of their high energy density. However, the formation of dendritic lithium during charge-discharge cycles poses significant safety risks. This study investigates the effects of thermal treatment on the surface morphology and Solid Electrolyte Interphase (SEI) formation of lithium metal anodes using Atomic Force Microscopy (AFM). Lithium metal samples were heat-treated at 100°C for 24 hours and then immersed in an electrolyte solution for different durations. AFM analysis revealed that thermal treatment increases the size and uniformity of nucleation sites. This results in a thicker and more stable native oxide layer. This enhanced layer promotes a more uniform and densely packed SEI, which remains stable over long-term immersion. The findings highlight the potential of thermal treatment to improve the performance and safety of lithium metal anodes by stabilizing the SEI and preventing dendritic growth. This advancement could significantly enhance the practical application of LMBs.

Abstract: This work only investigated the x-direction scanning of atomic force microscopy, which can accurately measure porous silicon's width, depth, and roughness. Pores on p-type Si (100) surfaces fabricated by electrochemical anodization method with the variation of resistivity and current density, i.e., 0.001-0.005 Ω.cm (high dopant) and 1-10 Ω.cm (low dopant), and 4, 6, 8, and 10 mA/cm², respectively. Macroporous silicon was obtained for both high and low dopants. Pore width, pore depth, and roughness of silicon increase with increasing the current density. Characteristics of porous silicon for high dopants are smaller than that for low dopants. It indicates that large amounts of dopant in silicon can slow the etching process.

Abstract: The possibility of anodic oxidation of SiC surfaces by a strong, local electric field applied during Atomic Force Microscopy (AFM) under ambient conditions is an interesting method to achieve nanopatterning of SiC, but is also a side-effect to be well characterized and controlled during this kind of AFM measurements if used to determine the local electric properties. In this contribution, we will analyze the local electric fields by finite element simulations in order to quantify the effect of the presence of a water meniscus and of an oxide layer on the SiC surface. Furthermore, we will experimentally highlight the strong influence of the local doping on the anodization, leading to the formation of thicker oxide layers at the location of highly doped SiC. Therefore, the location of these areas can be determined by a simple AFM topography scan after the application of a high field, allowing to detect highly doped SiC areas in complex structures as for example SiC MOSFETs.

Abstract: The feasibility of thin 4H-SiC layers bonded on an alternative carrier substrate for the application as substrate in SiC epitaxy is investigated. Epitaxial layers grown on such substrates are compared to those on state-of-the-art conventional substrates from different sources. The performance of the substrates is judged by the occurrence of killer defects in the epitaxial layer as analyzed using a PL scanning tool. Additional investigations on the material properties were carried out using X-ray topography and Atomic Force Microscopy, yielding information on the crystallinity, the lattice curvature, and the surface properties of the epitaxial layers.

Abstract: The use of Atomic Force Microscopy (AFM) to observe the microstructure of asphalt binder promises a better insight compared to other microscopy techniques. In this study, AFM was used to investigate the effect of nanosilica concentration and aging conditions on the microstructure of asphalt binders. Asphalt binder penetration grade of 60/70 was modified with nanosilica (NS) by varying its concentration ranging from 1% to 5% (with the increment of 1%). Nanosilica modified binder (NSMB) were aged using a pressure aging vessel (PAV). The microstructure of the NSMB before and after aging were characterized using tapping mode of the atomic force microscopy (AFM). The effect of nanosilica (NS) addition and PAV ageing on the phase distribution, size of ‘bee’ structure and surface roughness of the asphalt binder were investigated. Based on this study, it was found that the addition of NS into asphalt binder tended to increase the distribution of the catana phase, as well as increasing the size of the bee structure and surface roughness of the AFM image. Besides that, the after long-term ageing was applied, the number of the bee structure and distribution of catana and peri phase also increased. It can be concluded that the addition of NS and aging increased the overall surface stiffness of the bitumen and has made the material surface more solid-like.

Abstract: Establishing the relationship between the structure of solids, on the one hand, and macroscopic physical properties, on the other, makes it possible to obtain detailed information about the structure and nature of interactions in the system involved. The solution to this problem makes it possible to formulate recommendations for the creation of materials with specified properties. In this work, much attention is paid to polymer films of syndiotactic 1,2-polybutadiene (1,2-SPB). The properties of polymer films differ from the properties of bulk materials of the same chemical composition as films. The polymer (1,2-SPB) has an amorphous, irregular structure and, due to its significant irregular structure and makeup, has important electrical, physical and chemical properties. Its physical properties make this polymer promising for use in various fields of mechanical engineering, agriculture, construction, and healthcare. The paper reports the results of a study of relaxation processes by the method of thermoactivation spectroscopy of a relatively new polymer - syndiotactic 1,2-polybutadiene. The mechanisms of deformation and relaxation polarization are described and studied in detail. A technique for preparing samples and processing the experimental results of the dielectric characteristics of polymer films are described. Dielectric measurements were performed using a standard R-571 bridge. Experimental temperature dependences of dielectric constant, dielectric loss factor and loss tangent before and after exposure to a high-frequency electromagnetic field are shown. An atomic force microscopy (AFM) survey of a 1,2-SPB polymer film is presented. Particle analysis by AFM provides a unique opportunity to determine the size and shape of particles.

Abstract: High quality and behavior of steel is playing an essential role in metal and manufacturing industries. Hardox steel has exceptional properties includes high wear resistant and hardness. The wear behavior of hardox 400 steel was evaluated through pin on disc tribometer using different input constraints such as load, sliding velocity and disc speed. The wear worn surface was investigated through atomic force microscopy. The wear rate of the hardox steel was calculated with different load conditions. The wear factors and wear rate were optimized by taguchi method. Variance analysis was provided the contribution of each factor on mass loss.

Abstract: The mechanical impact-based energy harvesting behavior of a 0-3 Bi_0.5Na_0.5TiO₃/PVDF(25/75) composite prepared using the melt-mixing method have been demonstrated. X-ray diffraction analyses revealed the formation of a composite sample, while AFM image analyses revealed that BNT-particle sizes ranged between 0.6 and 1.4 μm and were evenly distributed throughout the polymer matrix, and surface roughness was found to be between 0.2 and 1.8 μm. With increasing impact height (applied mechanical energy), a remarkable increase in generated electric voltage and energy was observed. As a result, the present composite is a better lead-free alternative for piezo-sensing/detection and energy harvesting applications.

Abstract: The tensile deformation of NiTi alloy can proceeds in either homogeneous manner, or localized deformation via formation and propagation of macroscopic shear bands, that is commonly known as Lüders-like deformation. The high deformation strain within the localized deformed regions can result in the changes of surface characteristics of NiTi specimen. This paper studies the surface roughening effect associated with Lüders-like deformation of martensitic NiTi alloy, via surface characterization of polished surface and localized deformed region that consists of Lüders bands on tensile specimens, respectively. The surface roughness profile and roughness parameters of surface with Lüders bands are significantly different and higher as compared to the polished surface.