AFM Measurements Research Articles

Application of Atmospheric-Pressure Jet Plasma in the Presence of Acrylic Acid for Joining Polymers without Adhesives

This study investigates the treatment of surfaces with jet plasma at atmospheric pressure in the presence of acrylic acid as a resource-saving and efficient approach to joining polymers on polystyrene (PS) and polyamide 12 (PA 12) surfaces. Acrylic acid was added in order to introduce functional groups to the polymer surfaces. XPS analysis revealed a high density of oxygen-containing groups, e.g., carboxylic acid groups, on the polymer surfaces, the detailed composition depending on the polymer. The AFM measurements indicated that the modification of polyamide resulted in morphological changes and an increase in surface roughness due to polymer recrystallization. When the surface-modified polymers were brought in contact under a load, significant adhesion between the polymer surfaces was measured. In particular, PS and PA 12, which are otherwise difficult to join by gluing, could readily be connected in this way. The joint polymers could be separated intentionally by immersion in water, thus enabling the recycling of the materials. The resistance of the joint to water depends on the polymer system, with polyamide providing strikingly higher resistance than polystyrene. Accordingly, treating the joint polymers with water allows debonding on demand, particularly when PS is involved. Exposure of modified polymer surfaces to solutions of metal ions increased the resistance of joint polymers to water.

The Efficiency Study of Graphene Synthesis on Copper Substrate via Chemical Vapor Deposition Method with Methanol Precursor.

Few-layer graphene was successfully synthesized on copper foil via chemical vapor deposition with methanol as a carbon source. This was confirmed by optical microscopy observation, Raman spectra measurement, I2D/IG ratio calculation, and 2D-FWHM value comparisons. Monolayer graphene was also found in similar standard procedures, but it required higher growth temperature and longer time periods. The cost-efficient growth conditions for few-layer graphene are thoroughly discussed via TEM observation and AFM measurement. In addition, it has been confirmed that the growth period can be shortened by increasing growth temperature. With the H2 gas flow rate fixed at 15 sccm, few-layer graphene was synthesized at the lower growth temperature of 700 °C in 30 min, and at 900 °C growth temperature in only 5 min. Successful growth was also achieved without adding hydrogen gas flow; this is probably because H2 can be induced from the decomposition of methanol. Through further defects study of few-layer graphene via TEM observation and AFM measurement, we tried to find possible ways for efficiency and quality management in graphene synthesis in industrial applications. Lastly, we investigated graphene formation after pre-treatment with different gas compositions, and found that gas selection is a crucial factor for a successful synthesis.

Investigation into starch adsorption on hematite and quartz in flotation: Role of starch molecular structure

Various starches have been used as depressants in reverse flotation of iron ores. To date, the effect of molecular structures of starches on the depressing behavior is still not clear using simulation study. In this study, three starches with different ratios of amylose/amylopectin on the molecule (Normal Starch, Waxy Starch and Gelose 50) were used to study their depressing ability on the flotation of hematite and quartz. Microflotation, Zeta potential measurement, XPS analysis and AFM measurement were performed to investigate the interaction between the two minerals and the three starches. It was found that chemisorption occurred between hematite and the starches, while only hydrogen bonding was observed between quartz and the starches. In addition, it was obtained that the chemisorption strength between the starches and hematite under alkaline condition fell in the order: Waxy Starch > Normal Starch > Gelose 50, which was closely related to the ratios of amylose/amylopectin. The underlying mechanism for the different chemisorption strength was revealed via computational chemistry analysis. It is believed that the outcomes of this work could optimize the development of starch-based depressants in iron ore flotation.

Development of photocatalytic nanostructured TiO2 and NiO/TiO2 coatings by DC magnetron sputtering for photocatalytic applications

High photocatalytic activity layers were obtained by combining a TiO2 nanostructured coating support with 10 nm and 20 nm NiO layers synthesized by direct current (DC) magnetron sputtering. In order to improve the TiO2 crystallinity several sputtering process parameters were studied. The TiO2 and NiO/TiO2 coatings were characterized through XPS, XRD, FESEM, AFM and UV transmittance measurements, in the latter case, for band gap determination. The photocatalytic activity of the coatings was tested through methylene blue degradation under UV light. The formation of a p-n heterojunction between the TiO2 and NiO layers improved the degradation rates, compared to the bare TiO2 layers; however, almost no difference can be seen when increasing the NiO sputtering power and subsequently the coating thickness to higher values than 20 nm.

Synthesis and Characterization of Co-Modified Polyurethane Nanocomposite Latexes by Terminal and Pendant Fluoroalkyl Segments

To further improve the hydrophobic and thermal properties of fluorinated polyurethane (FPU), we initially prepared the fluorine- and silicon-containing pendant groups’ diols (DEFA and DESiA) by Michael addition reaction. Next, we synthesized a series of co-modified polyurethane nanocomposite (TPFPU-SiO2) latexes by terminal and pendant fluoroalkyl segments via varying the additive amount of silica sols. Structure and performance properties of the target materials were characterized by IR, TEM, TGA, DSC, XRD, XPS, SEM, AFM, and contact angle measurements. Results showed that with the increase in silica sols dosage, the mean particle size of the TPFPU-SiO2 latexes was increased and their emulsion stability gradually decreased. The thermal stability of the TPFPU-SiO2 films were gradually increased and hydrophobicity of the TPFPU-SiO2 films increased first and then slightly decreased. The maximum water contact angle on the TPFPU-SiO2 films was 119.8° and the lowest water absorptivity was 2.49%. Thus, these novel fluorinated polyurethane nanocomposite latexes can find valuable applications in heat-resistant and anti-fouling coatings.

Bi2Te3 Thin Films Deposited by the Combination of Bi and Te Plasmas in a PLD Process

Bismuth telluride thin films were grown by pulsed laser deposition by implementing a novel method that combines both Te and Bi plasmas resulting from the laser ablation of individual Bi and Te targets. Furthermore, the mean kinetic ion energy and density of the plasmas, as estimated by TOF curves obtained from Langmuir probe measurements, were used as control parameters for the deposition process. The obtained thin films exhibit a metallic mirror-like appearance and present good adhesion to the substrate. Morphology of the thin films was observed by SEM, yielding smooth surfaces where particulates were also observed (splashing). Chemical composition analysis obtained by EDS showed that apparently the films have a Te-rich composition (ratio of Te/Bi of 3); however, Te excess arises from the splashing as revealed by the structural characterization (XRD and Raman spectroscopy). The XRD pattern indicated that depositions have the rhombohedral (D3d5 (R3¯m)) structure of Bi2Te3. Likewise, Raman spectra exhibited the presence of signals that correspond to Eg2, A1u2 and A1g2(LO) vibrational modes of the same rhombohedral phase of Bi2Te3. Additionally, oxidation states, analyzed by XPS, resulted in signals associated to Bi3+ and Te2- that correspond to the Bi2Te3 compound. Finally, surface topology and thickness profiles were obtained from AFM measurements, confirming a combination of a smooth surface with particulates on top of it and a film thickness of 400 nm.

A facile novel synthesis of AgCuO2 delafossite nanoparticles and evaluation of their antimicrobial activity

Bi-functional nano-oxides are of growing interest to address environmental issues. In the present study, the structural and magnetic data are presented together with the antimicrobial activities (AMA). For the first time, silver delafossite oxide (AgCuO2) is successfully fabricated using a simple, low-cost technique to target antibiotic photodegradation and inactivation of model waterborne pathogens. It is prepared with an equimolar initial Ag+:Cu+ concentration ratio. The structure, morphology, and magnetic properties are studied by different characterization techniques. The size and shape of AgCuO2 NPs, in addition to their structural polytypes of 2H (hexagonal) or 3R (rhombohedral), are dependent on the preparation conditions. The existence of Cu, Ag, and O in the synthesized delafossite AgCuO2 NPs with no evidence of any impurity is ratified by the XPS spectrum. AFM measurements are taken to characterize the surface morphologies of AgCuO2. The distributed spiks are evaluated by roughness kurtosis (Rku). The roughness kurtosis has a value of 2.65 (< 3), indicating that the prepared sample is classified as bumpy. The prepared sample has 13.0, 10.0, 14.0, and 14.0 mm Inhibition Zone Diameter (IZD) antimicrobial activity against gram-positive Bacillus subtilis (B. subtilis), Bacillus cereus (B. cereus), Enterococcus faecalis (E. faecalis), and Staphylococcus aureus (S. aureus), respectively. The IZD for gram-negative Escherichia coli (E. coli), Neisseria Gonorrhoeae (N. Gonorrhoeae), Pseudomonas aeruginosa (P. aeruginosa), and Salmonella typhimrium (S. typhimrium) were found to be 12.0, 13.0, 14.0, and 13.0 mm, respectively. Therefore, the AgCuO2 NPs reveal excellent antimicrobial efficiency, and they can be effortlessly separated using a tiny magnet or a simple magnetic separator. The adequate cytotoxicity and magnetic characteristics of the antimicrobial sample suggest a promising future for it in biomedical applications.

Strontium/zinc phytate-based self-assembled monolayers on titanium surfaces enhance osteogenesis and antibacterial performance in vitro

The accumulation of bacteria over implant surfaces is still the first cause of failure, and the development of antimicrobial surfaces constitutes a first line in implant research. Besides, the durability and mechanical performance of implants, in special in the dental area, are mainly determined by their osseointegration capacity into the maxillofacial bone and the appearance of infections. Consequently, implant osseointegration and infection prophylaxis remain as big challenges to attain so a huge investigation is being developed on the production of bioactive surfaces to achieve improvements in these aspects. In this work we propose the functionalization of titanium surfaces (Ti Cp) with self-assembled monolayers (SAMs) of bioactive organophosphate compounds: phytic acid (Ti-PA) and its metallic phytate derivatives bearing Sr2+ and/or Zn2+ (Ti-SrPhy, Ti-ZnPhy and Ti-SrPhy/ZnPhy) which exhibited tunable in vitro osteogenic, antimicrobial and antioxidant properties in a previous work. Thus, phytate compounds are chemically anchored onto Ti discs through a simple procedure consisting of a condensation reaction promoted by heat treatment. EDS and XPS spectroscopies confirm the obtaining of the modified surfaces and the topographic properties and wettability analysed by SEM, AFM, profilometry and contact angle measurements, respectively, are explored. Additionally, phytate-SAMs do not release any cytotoxic compound after 14 days and stimulate in vitro adhesion and proliferation of human osteoblast cells after 14 days of culture. The osteogenic ability of the modified surfaces evaluated by the quantification of ALP activity and matrix mineralization degree shows a significant improvement with respect to unmodified surfaces. Furthermore, the antimicrobial activity of phytate-SAMs against Streptococcus mutans cultures is evaluated. The count of viable cells and the quantification of produced biofilm are significantly reduced by all phytate-SAMs groups (p < 0.001). Cell membrane integrity studies by LIVE/DEAD staining and SEM imaging confirm a decreased viability of adhered bacteria when phytate-based surfaces are tested, due to a disruption in the function and permeability of the cell membrane. Therefore, phytate-SAMs exhibit suitable in vitro features suggesting their promising potential as bioactive coatings of dental implants.

Wettability and corrosion resistance of zirconium nitride films obtained via reactive high-power impulse magnetron sputtering

One of the main problems in ships is corrosion, which reduces the lifetime usage of ship parts and increases maintenance costs. Ceramic coatings can contribute to solving this situation. Zirconium nitrides obtained by reactive unbalanced magnetron sputtering technology are largely reported as coatings with high corrosion resistance. The present study used high-power impulse magnetron sputtering in a reactive atmosphere (R-HiPIMS), varying the nitrogen amount. SEM, EDS, XRD, AFM, and contact angle measurements were used to assess the obtained coatings’ performance. Corrosion resistance was evaluated using electrochemical impedance spectroscopy (EIS) (up to 168 h exposure) and potentiodynamic polarization (PP) in NaCl (3.5% wt.—“artificial seawater”) solution. According to the results, cross section micrographs showed strong densification of ZrN films regardless of the nitrogen amount. Besides, nitrogen increases during deposition influenced the drop of applied peak power (Pp) to the target and, consequently, influenced other film properties, such as roughness, wettability, and corrosion resistance. PP and EIS tests demonstrate the protective behavior of films under artificial seawater exposure. The results prove that the implementation of HiPIMS technology to obtain ZrN films could contribute to increasing the corrosion resistance of coated ship metallic parts and, hence, help maritime transportation to reduce maintenance time and cost.

Study of Tribological Properties of Bulk Nanostructured Aluminum and Copper Samples Applicable in Automotive Bearing Application

Using lightweight systems and friction reduction approaches are two main contributors towards modern and efficient powertrains in the automotive industry. New materials and processes are required to achieve the demanding and ever-increasing performance requirement of automotive systems. Nanostructure induced by severe plastic deformation methods involves bimodal microstructures and hence, shows exceptional mechanical characteristics which can be exploited for automotive application. Through this study, samples were prepared using pure copper, aluminum alloy (series 7000) and were processed to attain bulk nanostructured samples using a Single Step High Pressure Torsion technique with appropriate dimensions applicable as the rolling elements of automotive bearings. The induced nanostructures resulted micro hardness and frictional characteristics of the bulk samples were assessed using transmission electron (TEM) and atomic force (AFM) microscopies as well as microhardness evaluations. The results revealed that a fully refined nanostructured samples were achieved with 90% increase in the hardness at the outer diameter of the sample. The AFM measurements indicated that the friction coefficient of nanostructured copper and aluminum samples were ~ 25 and ~ 45% less than that of both the unprocessed samples, respectively. Characteristics of treated samples suggest that these processes can be potentially used in demanding conditions of rolling element bearings with reduced weight and frictional losses.

Investigation of adsorption, corrosion inhibition, synergistic inhibition effect and stability studies of Rheum ribes leaf extract on mild steel in 1 M HCl solution

BackgroundDue to high cost, toxicity of conventional inhibitors and environmental regulations, corrosion scientists have directed toward plant extracts as alternatives to conventional inhibitors. In this study, leaf extracts of Rheum ribes (RR leaf) were prepared, and their adsorption and protective effects on mild steel (MS) corrosion were investigated in 1.0 M HCl solution. The synergistic inhibition effect of iodide ions and the stability of surface inhibitor film were also studied. MethodsThe protection ability of extract was investigated using electrochemical techniques. The stability of surface film was evaluated by potentiodynamic and potentiostatic studies. After being exposed to the corrosive medium, the surface of metal was examined using SEM, EDX, AFM and contact angle measurements. Significant FindingsThe extract molecules formed an adherent and homogenous protective film on the MS surface. When the RR leaf extract concentration increased, a stronger inhibition effect against corrosive attack was obtained. At 1000 ppm extract concentration, the protection efficiency of RR leaf extract increased from 91.8% to 94.9% when 1000 ppm KI was added to the inhibited acid solution. The extract molecules adsorbed to the metal surface via physical and chemical interactions. The surface extract film was very stable under potentiostatic or potentiodynamic conditions.

Antimicrobial-Loaded Polyacrylamide Hydrogels Supported on Titanium as Reservoir for Local Drug Delivery.

Arthroplasty is a highly successful treatment to restore the function of a joint. The contamination of the implant via bacterial adhesion is the first step toward the development of device-associated infections. The emerging concern about antimicrobial resistance resulted in a growing interest to develop alternative therapeutic strategies. Thus, the increment in the incidence of bacterial periprosthetic infections, the complexity of treating infections caused by organisms growing in biofilms, together with the rise in antibiotic resistant bacteria, expose the need to design novel surfaces that provide innovative solutions to these rising problems. The aim of this work is to develop a coating on titanium (Ti) suitable for inhibiting bacterial adhesion and proliferation, and hence, biofilm formation on the surface. We have successfully prepared polyacrylamide hydrogels containing the conventional antibiotic ampicillin (AMP), silver nanoparticles (AgNPs), and both, AMP and AgNPs. The release of the antibacterial agents from the gelled to aqueous media resulted in an excellent antibacterial action of the loaded hydrogels against sessile S. aureus. Moreover, a synergic effect was achieved with the incorporation of both AMP and AgNPs in the hydrogel, which highlights the importance of combining antimicrobial agents having different targets. The polyacrylamide hydrogel coating on the Ti surface was successfully achieved, as it was demonstrated by FTIR, contact angle, and AFM measurements. The modified Ti surfaces having the polyacrylamide hydrogel film containing AgNPs and AMP retained the highest antibacterial effect against S. aureus as it was found for the unsupported hydrogels. The modified surfaces exhibit an excellent cytocompatibility, since healthy, flattened MC3T3-E1 cells spread on the surfaces were observed. In addition, similar macrophage RAW 264.7 adhesion was found on all the surfaces, which could be related to a low macrophage activation. Our results indicate that AMP and AgNP-loaded polyacrylamide hydrogel films on Ti are a good alternative for designing efficient antibacterial surfaces having an excellent cytocompatibility without inducing an exacerbated immune response. The approach emerges as a superior alternative to the widely used direct adsorption of therapeutic agents on surfaces, since the antimicrobial-loaded hydrogel coatings open the possibility of modulating the concentration of the antimicrobial agents to enhance bacterial killing, and then, reducing the risk of infections in implantable materials.

Measuring the Diameter of Single-Wall Carbon Nanotubes Using AFM.

In this work, we identify two issues that can significantly affect the accuracy of AFM measurements of the diameter of single-wall carbon nanotubes (SWCNTs) and propose a protocol that reduces errors associated with these issues. Measurements of the nanotube height under different applied forces demonstrate that even moderate forces significantly compress several different types of SWCNTs, leading to errors in measured diameters that must be minimized and/or corrected. Substrate and nanotube roughness also make major contributions to the uncertainty associated with the extraction of diameters from measured images. An analysis method has been developed that reduces the uncertainties associated with this extraction to <0.1 nm. This method is then applied to measure the diameter distribution of individual highly semiconducting enriched nanotubes in networks prepared from polyfluorene/SWCNT dispersions. Good agreement is obtained between diameter distributions for the same sample measured with two different commercial AFM instruments, indicating the reproducibility of the method. The reduced uncertainty in diameter measurements based on this method facilitates: (1) determination of the thickness of the polymer layer wrapping the nanotubes and (2) measurement of nanotube compression at tube-tube junctions within the network.

Direct Processing of PVD Hard Coatings via Focused Ion Beam Milling for Microinjection Molding

Hard coatings can be applied onto microstructured molds to influence wear, form filling and demolding behaviors in microinjection molding. As an alternative to this conventional manufacturing procedure, "direct processing" of physical-vapor-deposited (PVD) hard coatings was investigated in this study, by fabricating submicron features directly into the coatings for a subsequent replication via molding. Different diamondlike carbon (DLC) and chromium nitride (CrN) PVD coatings were investigated regarding their suitability for focused ion beam (FIB) milling and microinjection molding using microscope imaging and areal roughness measurements. Each coating type was deposited onto high-gloss polished mold inserts. A specific test pattern containing different submicron features was then FIB-milled into the coatings using varied FIB parameters. The milling results were found to be influenced by the coating morphology and grain microstructure. Using injection-compression molding, the submicron structures were molded onto polycarbonate (PC) and cyclic olefin polymer (COP). The molding results revealed contrasting molding performances for the studied coatings and polymers. For CrN and PC, a sufficient replication fidelity based on AFM measurements was achieved. In contrast, only an insufficient molding result could be obtained for the DLC. No abrasive wear or coating delamination could be found after molding.

Graphene coated copper in a one-year atmospheric corrosion and color preserving challenge

A one-year atmospheric corrosion study was conducted to evaluate the performance of transparent single-layer (SLG) and multilayer graphene (MLG) coating as a protective coating on copper substrate against atmospheric corrosion and color changing. Employing the CIE−L*a*b* color space, it was shown that the transparent SLG and MLG coatings can maintain the pure color of copper before exposure to the atmosphere. However, after 15 days the color change (∆E) in the SLG-coated copper (SLG/Cu) was found to be more than that in the bare copper. A scanning Kelvin probe (SKP) was used to measure the surface potential as well as corrosion behavior. The observed decrease of average surface Volta potential of SLG/Cu, from -312 mV to -830 mV, was supposed to be caused by corrosion and electron transfer during galvanic cell formation. Further examinations by Raman spectroscopy, OM, and AFM measurements were logically correlated with those from SKP. Moreover, it was revealed that the surface voltaic potential for MLG-coated copper (MLG/Cu) remains constant along one-year atmospheric exposure. The presented results strongly prove that the MLG coating could be considered an anti-corrosion coating that can fully preserve the color of copper metal after exposure to the environment for at least a year.

Non-Conventional Peptide Self-Assembly into a Conductive Supramolecular Rope.

Structures composed of alternating α and β amino acids can give rise to peculiar secondary structural motifs, which could self-assemble into complex structures of controlled geometries. This work describes the self-assembly properties of an α,β-peptide, containing three units of syn H2-(2-F-Phe)-h-PheGly-OH, able to self-organize on surfaces into a fascinating supramolecular rope. This material was characterized by AFM, electronic conduction and fluorescence measurements. Molecular dynamics simulations showed that this hexapeptide can self-assemble into an antiparallel β-sheet layer, stabilized by intermolecular H-bonds, which, in turn, can self-assemble into many side-by-side layers, due to π-π interactions. As a matter of fact, we demonstrated that in this system, the presence of aromatic residues at the intramolecular interface promoted by the alternation of α,β-amino-acids in the primary sequence, endorses the formation of a super-secondary structure where the aromatic groups are close to each other, conferring to the system good electron conduction properties. This work demonstrates the capability and future potential of designing and fabricating distinctive nanostructures and efficient bioelectronic interfaces based on an α,β-peptide, by controlling structure and interaction processes beyond those obtained with α- or β-peptides alone.

MOVPE grown InGaAs quantum dots with emission near 1.3 [formula omitted]m for electrically driven single-photon sources

InGaAs quantum dots (QDs) with low areal density suitable for single-photon applications are fabricated on a GaAs substrate by MOVPE. AFM measurements used to investigate the dependency of QD density and size on the V/III ratio during growth reveal a low QD density of 3.2⋅107cm−2 for a high V/III ratio of 360. To allow for a targeted electrical excitation, the InGaAs QDs are embedded into a pin-LED structure containing an oxide aperture. Low temperature electroluminescence measurements show emission of a QD line at a wavelength of 1272.4 nm. Direct comparison of photoluminescence and electroluminescence spectra approve the electrical excitation of a single QD.

Investigation of the effects of CO2 annealing of polymer matrix composite anode electrodes used in Li-ion batteries

Recently, silicon with a high specific capacity (∼ 4000 mAh.g−1) is widely used as the anode material in Li-ion battery cells. However, it is known that due to changes in the structure of silicon particles during charge-discharge, they cause a decrease in the capacity of the system. CO2 annealing is applied on polymer matrix composite anode electrodes of Li-ion batteries to develop cell capacity and energy efficiency. The rearranged polymer structure and polymer Si particle interactions are effective in battery performance after annealing with CO2. In this study, Si/C/PVDF and LiCoO2 was preferred as the anode and the cathode, respectively. SEM, AFM and water contact angle measurements are applied to samples. With results, water repellence and surface roughness increased with increasing CO2 pressure. Samples annealed under CO2 shows better electrochemical performance and higher discharge capacities. The first charge capacity after CO2 is found to be 189 mAhg−1, and an improvement of 37% is achieved compared to the classical cell. The decrease of the surface energy of the electrode delays the diffusion of the electrolyte and thus the degradation of the structure of the polymeric electrode, thus improving the charge-discharge initial capacities. Besides, it is seen in the battery performance test results that the active surface area of the electrode increases thanks to the increasing surface roughness, and thus the capacity is positively affected.

Aerosol-Assisted Chemical Vapor Deposition (AACVD) Technique of SrTiO3: B Thin Films and Study the Structural and Optical Properties and Hall Effect Measurements

Aerosol-assisted chemical vapor deposition (AACVD) technique is very precise implemented to fabrication of structured SrTiO3 and Sr1-xBxTiO3 thin films at doping ratio (x = 2, 4, 6 and 8) % at temperature 400 °C on a glass substrate. The X-Ray Diffraction (XRD) patterns illustrated that the SrTiO3 and Sr1-xBxTiO3 thin films have a polycrystalline nature and cubic structure, the detailed characterization of the films by X-ray diffraction (XRD), the Surface Morphology studied by using (AFM) and (SEM). Have been noticed from AFM measurement the Roughness and RMS were increased with increases doping ratio. The optical properties of SrTiO3 and Sr1-xBxTiO3 thin films have been studied at doping ratio (x = 2, 4, 6 and 8) % at rate (300-900) nm. The transmittance spectrum is characterized by the opposite behavior of the absorbance spectrum. The transmittance generally increases with the increase in the wavelength of radiation, at wavelengths with low energies while the absorbance decreased slowly at spectrum rate (300-900) nm i.e. in the visible region. The band gap (Eg) is decreased at (3.2 - 2.5) eV which indicates that the doping process has led to the emergence of localized levels in the region confined by the valence and conduction bands, led to a reduction in the photon energy required for direct electronic transitions to occur. Found the carriers concentration charge are holes of Sr1-xBxTiO3 thin films at doping ratio (x = 2, 4, 6 and 8) %. Many properties can be improved by adding impurities such as Boron (B) to the SrTiO3, which can be used in solar cells, electronic industries or thermoelectric generators by controlling the optical or structural properties of the material by controlling the materials and percentages of impurity, or through heat treatment of the material, such as annealing, for example or exposure to different temperatures.

Production of spin coated chromium oxide (CrO3) thin layers and application in the Al/p-Si metal semiconductor structures

A novel Al/CrO3/p-Si structure was built by help the spin coating technique. CrO3 thin layer has been characterized by the XRD, UV–vis, SEM and AFM measurements. It has been observed that the CrO3 layer has amorphous structure with optical band energy value of 3.96 eV. The surface analysis of CrO3 layer by using AFM and SEM methods has been found to be rather rough that is not observed grains of any definite shape or size. Furthermore, some electronic quantities of Al/CrO3/p-Si junction by help the thermionic charge transport mechanism have been extracted by utilizing current-voltage (I-V) and capacitance-voltage data. Moreover, it has been seen that interfacial state concentration for the Al/CrO3/p-Si contact varied in the range of 8.05 × 1012 eV−1 cm2 to 6.71 × 1011 eV−1 cm−2 in darkness, and 1.23 × 1013 eV−1 cm−2 to 3.82 × 1012 eV−1 cm−2 under the illumination condition. The photoelectric parameters of the Al/CrO3/p-Si contact under 100 mW cm−2 light illumination was studied by I-V measurement.