The effect of different laser irradiation on rugometric and microtopographic features in zirconia ceramics: Study of surface statistical metrics

Investigation of microstructural, micromorphology, and surface plasmon resonance characteristics in Ni/Al, Ni/Cu, and Ni/SS thin films

As the first boundary between the environment and the material, the surface plays an important role in their interaction with each other, therefore, the use of appropriate tools and analysis to examine the mechanical properties and morphology of surfaces has particular importance in industry and research. In this research, a thin film of nickel was deposited on metal substrates made of aluminum, copper, and steel by using the RF magnetic cathode. Then, using a non-contact atomic force microscope, the morphological properties of the nickel film with static parameters, Minkowski functionals (MF's), fractal, and multifractal were extracted to be analyzed and studied. After that, using parameters such as root mean square (RMS) roughness, skewness, and kurtosis, it was determined how the surface roughness, distribution, and probability density of particles on the film surface alters with the change of the substrate. Next, by examining and analyzing the Δα and Δf parameters obtained from the multifractal section, the morphology of the produced film on the metal substrates was investigated. Then, the change in the surface plasmon resonance (SPR) peak position is changed for the prepared film in the range of the absorption spectrum due to the substrate effect and the microstructural properties of the formed film. HIGHLIGHTS: Ni film has been deposited by Rf magnetron sputtering. The effect of metal substrates on the topography, fractality, and optical properties was studied. Minkowski functionals were used to investigate the surface morphology of the samples. Substrate's material and the topography of the formed film can changed the surface plasmon resonance position.

Dual effect to improve the electrical properties of SZO films grown by nitrogen pneumatic spray pyrolysis

The principal aim of this study is to reduce considerably, via Sn doping, the resistivity of ZnO thin films prepared by simple, flexible, and cost-effective nitrogen pneumatic spray pyrolysis (NPSP) method on glass substrates at a temperature of 400°C. Different Sn content was tested (Sn/Zn = 0, 1, 3, 5 wt%) in an attempt to reduce the concentration of excessive oxygen atoms and create more free electrons. The microstructural, optical, morphological, and electrical properties of the films have been studied. The x-ray diffraction analysis demonstrated that tin-doped SZO films exhibited polycrystalline nature with a preferential orientation along (002) plane with the appearance of a new orientation (101) with the increase of Sn concentration leading then to bidirectional growth. The deposited SZO films showed an average optical transmittance of about 80% in the UV-visible region (200-800 nm) with optical band gap values at around 3.27 eV. Photoluminescence emissions of SZO samples presented three main peaks: near band edge emission, violet emission, and the blue-green emission. The surface morphology of the films obtained by scanning electron microscope (SEM) exhibited the change in morphology with increasing the Sn content. A minimum electrical resistivity value of about 17·10-3 Ω·cm was obtained for 3% SZO films. SZO films prepared by the NPSP method can be used as transparent window layer and electrodes in solar cells. RESEARCH HIGHLIGHTS: Highly oriented, conducting, and transparent Sn-doped ZnO films are successfully synthesized. The film growth orientation changed from mono-directional (002) axis to bi-directional (002) and (101) axis according to Sn doping. Ultraviolet and green emissions are noted by photoluminescence investigation. A minimum resistivity is observed for 3 wt% SZO film. The dual positive effect of the carrier gas used (N2) and Sn doping is confirmed.

Fractal Analysis on Surface Topography of Thin Films: A Review

The topographies of various surfaces have been studied in many fields due to the significant influence that surfaces have on the practical performance of a given sample. A comprehensive evaluation requires the assistance of fractal analysis, which is of significant importance for modern science and technology. Due to the deep insights of fractal theory, fractal analysis on surface topographies has been widely applied and recommended. In this paper, the remarkable uprising in recent decades of fractal analysis on the surfaces of thin films, an essential domain of surface engineering, is reviewed. By summarizing the methods used to calculate fractal dimension and the deposition techniques of thin films, the results and trends of fractal analysis are associated with the microstructure, deposition parameters, etc. and this contributes profoundly to exploring the mechanism of film growth under different conditions. Choosing appropriate methods of surface characterization and calculation methods to study diverse surfaces is the main challenge of current research on thin film surface topography by using fractal theory. Prospective developing trends are proposed based on the data extraction and statistics of the published literature in this field.

The effect of applied electric field on the micromorphology of Pt nanoparticles synthesized by laser ablation

In the present study, laser ablation technique (Nd:YAG) has been applied to synthesize platinum nanoparticles (NPs). Also, the effect of applied electric field on the physical, structural, and morphological properties of Pt NPs has been investigated during the nanosecond pulsed laser ablation of platinum. Based on the results extracted from TEM and scanning electron microscopy images, the formation of high percentage of NPs with spherical shape is demonstrated in all samples. The increase of applied electric field creates few rectangular, hexagonal, and rhombic NPs with the average size decreased from 20 to 9 nm. The significant influence of increasing electric field is also observed in UV-vis spectra by appearing the blue shift of the localized surface plasmon resonance peak. The UV-vis spectra also confirm the metallic nature of Pt NPs and the existence of inhomogeneous-sized particles and the coagulation of particle because of the long tail in higher wavelengths. In addition, atomic force microscopy images have been analyzed through MountainsMap Premium program and fractal dimension. As can be seen, increasing the applied electric field make the surface more irregular and the maximum value of D_f reveals the most irregular topography for sample with 50 V/cm electric field. Finally, the bending and stretching frequencies of the functional bending groups connected to the NPs surface have been characterized by Fourier transform infrared spectroscopy. Electrical field-assisted laser ablation in liquids method allows a better control of the size, morphology, structure, and chemical composition of nanoparticles.

Atomic force microscopy studies of enamel, inner enamel, dentin, and cementum in canine teeth

The main goal of the present work is to explore the three dimensional (3-D) atomic force microscopy (AFM) images of human teeth and investigating their micromorphology. For this purpose, 10 fresh and permanent canine teeth were selected from a group of 40-year-old men who were candidate for the experimental processes. Afterward, they were all applied for studying the morphology of their hard tissues. The tapping mode of AFM was used to characterize the surface micromorphology on the square areas of 1 μm × 1 μm (512 × 512 pts). AFM results and surface stereometric analysis indicate the relationships between the micromorphology of the surface and the structural properties of these tissues across the length scales. As can be seen, the surface of cementum has the most irregular topography (D = 2.87 ± 0.01) while the most regular topography (D = 2.43 ± 0.01) is found in dentin. Furthermore, the more and less regularity of the surface have been found in inner enamel (Sq = 26.26 nm) and dentin (Sq = 41.28 nm), respectively. Stereometric and fractal analyses give valuable information about human canine teeth via 3-D micromorphology.

Physical Properties, Spectroscopic, Microscopic, X-ray, and Chemometric Analysis of Starch Films Enriched with Selected Functional Additives

Biodegradable materials are used in the manufacture of packaging and compostable films and various types of medical products. They have demonstrated a large number of potential practical applications in medicine and particularly in the treatment of various cardiac, vascular, and orthopedic conditions in adults as well in children. In our research, the extrusion-cooking technique was applied to prepare thermoplastic starch (TPS), which was then utilized to obtain environmentally friendly starch-based films. Potato starch was the basic raw material exploited. Polyvinyl alcohol and keratin were used as functional additives in amounts from 0.5 to 3%, while 20% of glycerol was harnessed as a plasticizer. The processing of the thermoplastic starch employed a single screw extruder-cooker with an L/D ratio of 16. The film blowing process was carried out using a film-blowing laboratory line with L/D = 36. FTIR Spectroscopy was applied for the assignment of the prominent functional groups. The results showed that the processing efficiency of thermoplastic starch with functional additives varied depending on the level of polyvinyl alcohol and keratin addition. Moreover, the FTIR data correlated with the changes in the physical properties of the tested films. The analysis of FTIR spectra revealed several changes in the intensity of bands originating from stretching vibrations characteristic of the –OH substituent. The changes observed depended on the presence/lack of the hydrogen bonding occurring upon interactions between the starch molecules and the various additives used. In addition, notable changes were observed in bands assigned to glycoside bonds in the starch.

The effect of deposition times in DC-magnetron sputtering on micromorphology of TiO2 thin films

TiO₂ thin films have been prepared by DC-magnetron sputtering process with various deposition times (8, 14, 16, and 20 min) and the micromorphology of their surface has been investigated by means of multifractal analysis. As the main purpose of the manuscript, the topography of all samples are examined by atomic force microscopy (AFM) through the Mountains Map® Premium software which characterizes motifs of significant peaks and pits through stereometric data by the watershed segmentation algorithm. In addition, multifractal features of samples provide deeper insight into texture characteristics and used as the supplementary of the results.

3D micromorphology evaluation of kefir microbial films loaded with extract of Amazon rainforest fruit Cupuaçu

We performed qualitative and quantitative analysis of surfaces of kefir biofilms loaded with Amazon rainforest fruit extract. Scanning electron microscopy and atomic force microscopy were used to evaluate the micromorphology of the biofilms. The films surface displayed a lower density of microorganisms (∼ 0.061 microorganisms/μm²) for the lowest concentration of fruit extract, however, a greater density (∼0.220 microorganisms/μm²) was observed for the higher concentration. Height stereometric parameters revealed that the biofilms with the highest concentration presented the highest roughness. However, almost all the stereometric parameters related to texture showed no significant difference. Furthermore, the Hurst coefficients of the average power spectrum density were similar for all biofilms. Fractal parameters confirmed that higher concentrations of fruit extract induced a superior topographic irregularity. However, fractal lacunarity does not show any significant difference confirming the similarity of the microtextures. Moreover, fractal succolarity and surface entropy exhibited values that suggested ideal percolation and strong topographic uniformity, respectively, indicating that these films can uniformly adhere to other surfaces. Our results confirm that the stereometric and fractal parameters can be relevant for the surface characterization of microbial films, which can be of great importance to the biomedical field.

The relation between the average diameter of CNTs on Ni-Cu @ a-C:H catalyst with the optical absorption edge and the optical dispersion parameters

In this study, the average diameter of the grown CNTs on Ni-Cu NPs @ a-C:H substrates were increased by increasing of Cu content. The obtained results indicated that by increase of Cu content, all films exhibited high-absorption spectra; therefore, we were facing an increase in the energy gap of films. The values of dT/dλ and dR/dλ measurements for grown CNTs with 75% Cu shown that maximum values of optical band gap correspond to with values of 2.48 eV and 2.90 eV, respectively. It can be seen that with increase of average diameter of the grown CNTs,  the values of Urbach energy of films were increased. The RBS and EDAX measurements were confirmed presence of Ni and Cu atoms into films. The films deposited with 75% Cu were more smooth. Films deposited with 75% Cu have more disordered. Films deposited with 75% Cu atoms have maximum values of the oscillator strength f and the dispersion energy E_d about of 0.108 eV² and 0.0543 eV, respectively.

Micromorphology analysis of TiO2 thin films by atomic force microscopy images: The influence of postannealing

This work describes an analysis of titanium dioxide (TiO₂ ) thin films prepared on silicon substrates by direct current (DC) planar magnetron sputtering system in O₂ /Ar atmosphere in correlation with three-dimensional (3D) surface characterization using atomic force microscopy (AFM). The samples were grown at temperatures 200, 300, and 400°C on silicon substrate using the same deposition time (30 min) and were distributed into four groups: Group I (as-deposited samples), Group II (samples annealed at 200°C), Group III (samples annealed at 300°C), and Group IV (samples annealed at 400°C). AFM images with a size of 0.95 μm × 0.95 μm were recorded with a scanning resolution of 256 × 256 pixels. Stereometric analysis was carried out on the basis of AFM data, and the surface topography was described according to ISO 25178-2:2012 and American Society of Mechanical Engineers (ASME) B46.1-2009 standards. The maximum and minimum root mean square roughnesses were observed in surfaces of Group II (Sq = 7.96 ± 0.1 nm) and Group IV (Sq = 3.87 ± 0.1 nm), respectively.

Multifractal analysis of human canine teeth at nano scale: atomic force microscopy studies

The aim of the present study is to explore the 3-D micromorphology of human canine teeth materials using multifractal analysis through atomic force microscopy (AFM). The 3-D surfaces of ten extracted canine teeth of a group of 40 year old men were studied (enamel, inter enamel, inter dentin, and cementum) by AFM images in tapping mode and on square areas of 1 μm × 1 μm (512 × 512 points). The AFM images and surface multifractal analysis confirm the dependency of surface micromorphology to their structure–property of these materials across the length scales of the teeth structural architecture. Surface statistical parameters and hence, multifractal approach have been considered as reliable and sensitive tools for quantifying the 3-D surface microtexture changes of human canine teeth materials. The surface of inter dentin had the most irregular topography (the width spectrum Δα = 2.8361, value bigger than all the other Δα sample values), while the most regular topography (the width spectrum Δα = 2.6804, value lower than all the other sample values) was found in cementum. It has been concluded that multifractal analyses can be used as mathematical tools to explore the 3-D micromorphology of human canine teeth materials.

The surface effect on the thermodynamic stability, half-metallic and optical properties of Co2MnGa(001) films: a DFT study

In this study, the half-metallic properties, thermodynamic stability and optical parameters of the full-Heusler Co2MnGa compound and its four different terminations of Co–Co, Co–Mn, Mn–Ga and Co–Ga from the surface of Co2MnGa (001) have been calculated based on the density functional theory (DFT). The results confirm the ferromagnetic half-metallic behavior with a magnetic moment of 4.08 $$ \mu_{\text{B}} $$μB and a gap of 0.32 eV at the Fermi level of Co2MnGa bulk phase having a Cu2MnAl-type structure. The density of states curves showed that all possible terminations from the Co2MnGa (001) surface eliminate the half-metallic behavior except the termination of Mn–Ga case. Moreover, the results indicate that the termination of Mn–Ga with the lowest surface energy is the most stable termination for the application in spintronics. The optical coefficients such as real and imaginary dielectric function, refraction, extinction, energy loss function, optical conductivity and reflections of the bulk and Mn–Ga termination have been calculated and compared.

Topographic characterization of canine teeth using atomic force microscopy images in nano-scale

The purpose of the present study was to investigate a new method to evaluate micro topography and micro morphology of hard tissue of canine teeth using an atomic force microscope (AFM). For this aim, three extracted human canine teeth were applied. The unpolished surfaces were analyzed with AFM images with 15 µm × 5 µm area and their information obtained by power spectral density (PSD) method and fast Fourier transform algorithm. It was observed that PSD analyses extract suitable information about surface morphological variations so that by moving from enamel to cementum, the fractal dimension and surface complexity were increased.

The effects of deposition time on the nanoscale patterns of Ag/DLC nanocomposite synthesized by RF-PECVD

INTRODUCTION

In this study, a stereometric analysis of the three dimensional (3-D) surfaces of the Ag/DLC nanocomposite synthesized by RF-PECVD was performed.

MATERIALS AND METHODS

Atomic force microscopy in noncontact mode was used to study surface morphology in correlation with multi-parametric statistical analysis. The associated parameters of segmented motifs in conformity with ISO 25178-2:, 2012 have been extracted using MountainsMap® Premium software. The mathematical algorithm computes detached watersheds of hill or dale motifs and determines the maximum and minimum points of motifs.

RESULTS AND DISCUSSION

The stereometric analyses with MountainsMap® Premium software provided detailed information on the 3-D surface topography of samples. Fractal analyses revealed the fractal nature of the performed samples is in correlation with the deposition time of samples. Detailed information of manufactured Ag/diamond-like carbon (DLC) nanocomposite is given based on the information about the surface structure, properties, and performance characteristics. The performed analysis allows the high-resolution modeling of Ag/DLC nanocomposite surface microtexture with motif analysis (intrinsic characteristics disclosure and characterization of surfaces fractal), in order to be included in computer interactive simulation algorithms.

CONCLUSION

It was found the fractal dimension decreases with the increase of the deposition times on samples.