Radio Frequency Magnetron Sputtering Technique Research Articles

Development of room-temperature operable TiO2-x-based hydrogen gas sensor with light irradiation

In this research work, TiO2-x-thin films are deposited through a radio-frequency magnetron sputtering technique by varying the oxygen partial pressure (pO2) of 6.0 %, 6.4 %, and 6.8 %. The X-ray diffraction analysis depicts the formation of the anatase phase of the annealed thin film with a high crystalline nature. The existence of higher oxygen vacancies and surface roughness are confirmed by the X-ray photoelectron spectroscopy and the atomic force microscopy analyses, respectively, in the 6.0 % pO2 grown thin film. At room temperature (30 °C) and dark conditions, the optimized TiO2-x-based hydrogen gas sensor device depicts a notable response of 22.9 % on exposure to 100 ppm of H2 gas. The irradiation of the ultra-violet (UV) light (λ = 365 nm) on the sensing material promotes desorption of the oxygen species and hence improves the responsivity of the sample. The highest responsivity of 87.7 %, along with faster response and recovery time of 9.4 s and 7.8 s, respectively, is achieved under the UV light irradiation and 100 ppm of H2 gas for the sample grown at 6.0 % pO2, which signifies its potential for the development of room temperature operable hydrogen gas sensor.

Biological and Physicochemical Analysis of Sr-Doped Hydroxyapatite/Chitosan Composite Layers.

In this work results are presented on the evaluation of HAp, HApSr, HAp_CS, and HApSr_CS layers deposited on Ti substrates regarding L929 cell viability and cytotoxicity as well as antimicrobial activity against Staphylococcus aureus, in connection with their physicochemical properties. The HAp and HApSr layers generated by radio-frequency magnetron sputtering technique were further covered with chitosan by a matrix-assisted pulsed laser evaporation technique. During the plasma depositions, the Ti substrates were heated externally by a home-made oven above 100 °C. The HApSr_CS layers generated on the unpolished Ti substrates at 100 °C and 400 °C showed the highest biocompatibility properties and antimicrobial activity against Staphylococcus aureus. The morphology of the layer surfaces, revealed by scanning electron microscopy, is dependent on substrate temperature and substrate surface roughness. The optically polished surfaces of Ti substrates revealed grain-like and microchannel structure morphologies of the layers deposited at 25 °C substrate temperature and 400 °C, respectively. Chitosan has no major influence on HAp and HApSr layer surface morphologies. X-ray photoelectron spectroscopy indicated the presence of Ca 2p3/2 peak characteristic of the HAp structure even in the case of the HApSr_CS samples generated at a 400 °C substrate temperature. Fourier transform infrared spectroscopy investigations showed shifts in the wavenumber positions of the P-O absorption bands as a function of Sr or chitosan presence in the HAp layers generated at 25, 100, and 400 °C substrate temperatures.

Hemocompatibility and Preangiogenic Attributes of SiBxCyNzOm Coatings for Biomedical Applications.

In current clinical practices related to orthopedics, dental, and cardiovascular surgeries, a number of biomaterial coatings, such as hydroxyapatite (HAp), diamond-like carbon (DLC), have been used in combination with metallic substrates (stainless steel, Ti6Al4V alloy, etc.). Although SiBCN coatings are widely explored in material science for diverse applications, their potential remains largely unexplored for biomedical applications. With this motivation, the present work reports the development of SiBxCyNzOm coatings on a Ti6Al4V substrate, employing a reactive radiofrequency (RF) magnetron sputtering technique. Three different coating compositions (Si0.27B0.10C0.31N0.07O0.24, Si0.23B0.06C0.21N0.22O0.27, and Si0.20B0.05C0.19N0.20O0.35) were obtained using a Si2BC2N target and varying nitrogen flow rates. The hydrophilic properties of the as-synthesized coatings were rationalized in terms of an increase in the number of oxygen-containing functional groups (OH and NO) on the surface, as probed using XPS and FTIR analyses. Furthermore, the cellular monoculture of SVEC4-10 endothelial cells and L929 fibroblasts established good cytocompatibility. More importantly, the coculture system of SVEC4-10 and L929, in the absence of growth factors, demonstrated clear cellular phenotypical changes, with extensive sprouting leading to tube-like morphologies on the coating surfaces, when stimulated using a customized cell stimulator (StimuCell) with 1.15 V/cm direct current (DC) electric field strength for 1 h. In addition, the hemocompatibility assessment using human blood samples revealed clinically acceptable hemolysis, less erythrocyte adhesion, shorter plasma recalcification, and reduced risk for thrombosis on the SiBxCyNzOm coatings, when compared to uncoated Ti6Al4V. Taken together, the present study unambiguously establishes excellent cytocompatibility, hemocompatibility, and defines the preangiogenic properties of SiBxCyNzOm bioceramic coatings for potential biomedical applications.

Investigation on thermoelectric properties of SnSe thin films as prepared by RF magnetron sputtering

In this work, we investigated the thermoelectric properties of SnSe (Tin Selenide) thin films onto SiO2/Si-wafer substrates as prepared by RF (radio frequency) magnetron sputtering technique. The sputtering conditions used base pressure below 5.5 10−4 Pa and working pressure at 0.93 Pa within the Ar atmosphere as a flow rate fixed 40 sccm. The RF sputtering power was applied at 80 W and sputtering time for 30 min. After thin film deposition, as-deposited thin films were annealed by the vacuum annealing method at 300–450 °C. The crystal structure, morphology and film thickness, and atomic composition of SnSe thin film were carried out by X-ray diffraction (XRD), the field emission scanning electron microscope (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) techniques, respectively. The thermoelectric properties (electrical resistivity; ρ) and Seebeck coefficient; S) were measured by the ZEM-3 method to calculate the power factor (PF) value. The results showed that the as-deposited thin films had improved the crystallography of SnSe from amorphous to crystalline phases after thin films were annealed at a temperature range of 300–400 °C. At room temperature, the maximum power factor of 0.35 mW m˗1 K˗2 (ρ = 202 mΩ m and S = 165 μV K˗1) could be found to estimate the dimensionless Figure of Merit (ZT) values around 0.44 for annealing thin film sample at 400 °C.

The Impact of Temperature and Power Variation on the Optical, Wettability, and Anti-Icing Characteristics of AZO Coatings

The structural, wettability, and optical characteristics of aluminum-doped zinc oxide (AZO) thin films were studied with the objective of understanding the impact of deposition power and deposition temperature. Thin films were deposited using a radio frequency (RF) magnetron sputtering technique. The power output of the RF was augmented from 200 to 260 W, and the temperature was increased from 50 to 200 °C, which led to the development of a (002) peak for zinc oxide. The study of film thickness was carried out using the Swanepoel envelope method from data obtained through the UV-Vis spectrum. An increase in surface roughness value was shown to be connected with fluctuations in temperature as well as increases in deposition power. The findings revealed that as deposition power and temperature increased, the value of optical transmittance decreased, ranging from 70% to 90% based on the deposition parameters within the range of wavelengths that extend from 300 to 800 nm. The wettability properties of the samples were studied, and the maximum contact angle achieved was 110°. A Peltier apparatus was utilised in order to investigate the anti-icing capabilities, which revealed that the icing process was slowed down 3.38-fold. This work extends the understanding of the hydrophobicity and anti-icing capabilities of AZO thin films, specifically increasing both attributes which provide feasible options for purposes requiring resistance to ice.

Effect of Deposition Working Power on Physical Properties of RF-Sputtered CdTe Thin Films for Photovoltaic Applications.

The main objective of this study was to determine the variation in the properties of cadmium telluride (CdTe) thin films deposited on a p-type Si substrate by the radio frequency magnetron sputtering technique at four different working powers (70 W, 80 W, 90 W, and 100 W). The substrate temperature, working pressure, and deposition time during the deposition process were kept constant at 220 °C, 0.46 Pa, and 30 min, respectively. To study the structural, morphological, and optical properties of the CdTe films grown under the mentioned experimental conditions, X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical spectroscopy were used. For a better analysis of the films' structural and optical properties, a group of films were deposited onto optical glass substrates under similar deposition conditions. The electrical characterisation of Ag/CdTe/Al "sandwich" structures was also performed using current-voltage characteristics in the dark at different temperatures. The electrical measurements allowed the identification of charge transport mechanisms through the structure. New relevant information released by the present study points towards 90 W RF power as the optimum for obtaining a high crystallinity of ~1 μm nanostructured thin films deposited onto p-Si and optical glass substrates with optical and electrical properties that are suitable for use as absorber layers. The obtained high-quality CdTe nanostructured thin films are perfectly suitable for use as absorbers in CdTe thin-film photovoltaic cells.

Highly oriented crystalline si on epitaxial Gd2O3/Si(111) substrate using low-cost Radio Frequency sputtering for Silicon on Insulator application

Silicon-on-Insulator (SOI) technology has been the center of attraction with the advancement in Radio Frequency (RF) technology and the advent of Internet-of-Things due to its low-power operation with reduced parasitic and short-channel effects. However, the state-of-the-art smart-cut method used for the SOI wafer is costly. Alternatively, the notion of using the Si channel layer on epitaxial rare-earth oxide has been proposed. In literature, the existing techniques used to achieve the same, such as Molecular beam Epitaxy or reduced-pressure chemical vapor deposition technique, are either costly or non-high-volume manufacturable. In this context, we propose a method to fabricate the highly oriented crystalline Si(111) channel layer (Top-Si) on an epitaxial Gd2O3/Si(111) virtual substrate (SOXI) utilizing the solid phase epitaxy using the high-volume manufacturing friendly (HVM), low-cost RF magnetron sputtering technique. First, we have shown the multicrystalline Si and epitaxial Gd2O3 layer grown on Si(111) substrate, as confirmed using high-resolution X-ray diffraction (HRXRD) and Transmission Electron Microscopy (TEM). Second, we investigated the impact of rapid thermal annealing at 850 °C on the heterostructure using HRXRD and TEM. It is observed that the high-temperature annealing transforms the Top-Si layer into the highly oriented crystalline Si(111) layer by fusing smaller grains towards larger grains. Hence, we demonstrate a low-cost, HVM-friendly technique for the fabrication of SOXI wafers.

Fabrication of garnet solid electrolytes via sputtering for solid-state batteries

In this study, the deposition of Li7La3Zr2O12 (LLZO) thin films onto MgO substrates was successfully achieved using the radio frequency magnetron sputtering technique. The deposition process was carried out at various substrate temperatures to investigate their influence on the film properties The as-deposited films were initially amorphous; however, they could be crystallized into the cubic phase by increasing the deposition temperature above 100 °C. Upon raising the deposition temperature to 200 °C, the peaks in the X-ray diffraction pattern became sharper and more intense, indicating an increase in the volume fraction and crystallite size of LLZO.At 200 °C, the film consisted predominantly of the conductive crystalline LLZO phase, resulting in a remarkably high ionic conductivity of about 10−4S cm−1. The film deposited at 300 °C exhibited the second phase, i.e., the La2Zr2O7 phase, which resulted from excessive lithium losses. These findings highlight the importance of controlling the deposition temperature to achieve the desired crystalline phase and optimize the electrical properties of LLZO thin films.

Modulation of electrical properties of sputtered Ta2O5 films by variation of RF power and substrate temperature

Dielectric thin films are important building blocks of microelectronic devices, and hence, research on the development of high-k dielectric thin films has drawn tremendous research interest. In this research, thin films of tantalum oxide (Ta2O5), a high-k dielectric material, are deposited on the Si substrate by the radio frequency (RF) magnetron sputtering technique. During the deposition of Ta2O5 thin film, the sputtering parameters such as sputtering power and substrate temperature were systematically varied, and post-deposition structural, morphological, and electrical properties of sputtered Ta2O5 films are studied by x-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscope, capacitance–voltage (C-V) and current–voltage (I-V) measurement techniques. The annealed Ta2O5 thin film at the temperature of 900 °C for 1 h possesses polycrystalline nature with β—phase orthorhombic crystal structure. The film deposited at 150 W and substrate temperature at room temperature has shown comparatively lower surface roughness, which depicts the energy, and mobility of adatoms greatly influenced by RF power and substrate temperature. With the increase in sputtering power, the oxide charge density (Qox) is found to increase. On the other hand, Qox is found to decrease with the increase in substrate temperature. The film deposited at RF power of 150 W and substrate temperature of 300 °C is found to be of high dielectric constant, low oxide and interface charge density, and lower leakage current.

Effects of applied negative bias voltage on the optical and structural properties of CaF2 coatings deposited by RF magnetron sputtering

Calcium fluoride (CaF2) is a ceramic material exhibiting versatile properties including broadband transparency, lubrication at high temperature, and mechanical stability. In the current research, aimed at improving optically-driven infrared detection devices, CaF2 coatings were deposited on sapphire. One challenge concerning this CaF2/sapphire system is the significant difference between their coefficients of thermal expansion, which can cause adhesion failure. To avoid such failure, we first studied the behavior of thick CaF2 coatings on silicon substrates where adhesion issues are expected to be more pronounced, then employed thin CaF2 coatings, initially on silicon and subsequently on sapphire substrates.Deposition was carried out by radio frequency magnetron sputtering technique in an argon atmosphere at a fixed power of 4.4 W/cm2. Substrate bias voltage was varied from 0 to - 150 V in order to explore voltage impact on properties of the obtained CaF2 coatings.Coatings deposited with low negative bias voltages presented an inhomogeneous surface with a columnar structure that remained firmly attached to the substrate; optical transmission for these coatings was reduced relative to that for bare sapphire. Alternatively, while coatings deposited with high negative bias voltages became dense and uniform, they were also subjected to high surface reactivity causing formation of CaO/Ca(OH)2 phases and defects, as well as delamination that reduced optical transmission. In contrast, only samples deposited with moderate bias voltages exhibited a sufficiently dense, highly adhesive layer, resulting (relative to that for bare sapphire) in improved optical transmission. Thin CaF2 coatings deposited with −100 V improved transmittance (at a wavelength of 1.9 μm) from almost 88.5 %–92 %, representing approximately a 30 % decrease in radiation loss caused by absorbance, scattering, and reflectance effects. Even though the optical values of transmittance for increased wavelength (up to 5 μm) were reduced, these values still surpassed those obtained for sapphire alone.

High quality Mn-Co-Ni-O based infrared detectors enhanced by Pt nanoparticle decoration

The work developed a series of infrared detectors based on the Mn-Co-Ni-O (MCNO) films, which were grown using a radio frequency (RF) magnetron sputtering technique. It was observed that the characteristics of MCNO films were significantly impacted by the annealing temperature. Elevating the in-situ annealing temperature from 550 to 750 °C improved the performances of MCNO films. Additionally, it was found that in situ annealing was more advantageous than ex-situ annealing of 750 °C for the properties of MCNO films. The response value (light to dark) increased from 2.5 to 17.7 at 15 V bias, representing a 6.08-fold enhancement, and the response time decreased to 11.8 ms from 19.9 ms. Furthermore, sputtering Pt nanoparticles on the surface of the MCNO film further improved the I-V characteristics in the dark, resulting in a high on/off ratio of 38.15, which is five times higher than that without the Pt nanoparticles modification. This impressive improvement in photoproperties can be attributed to the Pt nanoparticles/MCNO film barrier, plasma resonance effect generated by the Pt nanoparticles, the extinction of the Pt nanoparticles, and the reduction of surface resistance caused by the Pt nanoparticles. This highlights the potential of metal nanoparticles in the development of infrared detectors.

In2S3 thin films with potential use as window layers in photovoltaic devices

In this study, we use the Haacke’s figure of Merit (FOMH) as a valuable parameter for determining suitable Indium Sulphide thin films among a set of samples processed with different deposition parameters, in order to use them as window layers in the usual configuration of photovoltaic devices. Two sets of In2S3 thin films were deposited by radiofrequency (RF) magnetron sputtering technique with an average thickness around 90 nm and using different deposition parameters. One set of samples was processed using different RF power in the range of 75–250 W at room temperature, the second set was obtained using different substrate temperatures 24 °C–350 °C keeping a constant RF power at 75 W. The FOMH consider optical and electrical properties of In2S3 thin films in order to evaluate the feasibility of the thin film to be used as a window layer in photovoltaics devices. The In2S3 thin films processed by RF-Sputtering were analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Ultraviolet-Visible spectroscopy, Raman spectroscopy, x-ray diffraction (XRD) and four-probe method. The In2S3 thin films had a high optical transmittance of 84% and the energy band gap values of the films decreased from 2.48 to 2.38 with the increase in substrate temperature and deposition power. The estimated grain size decreasing from 65 to 45 nm as the RF power increased. Additionally, the crystallinity of the selected In2S3 thin films was analyzed by Raman and XRD and showing that the cubic and tetragonal β-In2S3 phases can coexist in the films. The In2S3 thin films showed resistivity vales around Higher values of FOMH were obtained for In2S3 thin films processed at 75 W, 250 W, 100 °C and 300 °C, therefore these layer are feasible candidates to be used as window layers in photovoltaic devices.

Tunable room-temperature ferromagnetism in RF magnetron sputtered Al2Cr2Cu2O8 thin film

Metal oxide solid solution thin films containing ternary mixtures of Alumina (Al2O3), Chromia (Cr2O3) and Cupric oxide (CuO) were successfully prepared combinatorially on FTO, quartz glass and Si substrates using radio frequency (RF) magnetron sputtering (vertical geometry; on-axis sputtering) technique with RF powers of 200 W and 100 W. XRD analysis prove the development of tetragonal phase Al2Cr2Cu2O8 in sputtering target. Al2Cr2Cu2O8 film deposited on Si wafer and quartz glass exhibits amorphous nature, whereas, the film deposited on FTO substrates exhibit crystalline structure with tetragonal phase owing to polycrystalline nature of the FTO substrates. Formation of high compositional purity with acceptable stoichiometric ratio of ternary metal oxide mixtures of Al2Cr2Cu2O8 was ascertained from the EDX spectra. The thicknesses of Al2Cr2Cu2O8 thin films are found to be in the ranges from 259 to 314 nm. Optical study showed that the optical energy band gap of Al2Cr2Cu2O8 thin film deposited on quartz substrates increased to 3.84 eV from 3.78 eV with decreasing RF power from 200 W to 100 W. The spin orbital splitting (SOS) between Cr 2p1/2 - Cr 2p3/2 and Cu 2p1/2 - Cu 2p3/2 were measured to be 9.9 eV and 19.3 eV by XPS for 200 W sputtered Al2Cr2Cu2O8 film on quartz substrate, which are the characteristics of Cr3+ and Cu2+ oxidation states, respectively. In addition, XPS analysis also confirms the presence of various oxygen vacancies in Al2Cr2Cu2O8 thin films (as-deposited and 1000 °C annealed films) on quartz substrate with RF power of 200 W, which is the most favorable condition for the presence of room temperature ferromagnetic properties observed in the present study.

Spectral Analysis of Strontium-Doped Calcium Phosphate/Chitosan Composite Films.

Strontium-doped calcium phosphate/chitosan films were synthetized on silicon substrates using the radio-frequency magnetron sputtering technique and the matrix-assisted pulsed laser evaporation technique. The deposition conditions associated with the radio-frequency magnetron sputtering discharge, in particular, include the high temperature at the substrate, which promotes the formation of strontium-doped tetra calcium phosphate layers. The physical and chemical processes associated with the deposition of chitosan on strontium-doped calcium phosphate layers were investigated using Fourier Transform Infrared Spectroscopy, Energy Dispersive X-ray Spectroscopy, and Scanning Electron Microscopy. Mass spectrometry coupled with laser induced ablation of the composite films proved to be a useful tool in the detection of the molecular ions characteristic to chitosan chemical structure.

A comparative study of photoelectric performance of Ga2O3 solar-blind photodetectors with symmetric and asymmetric electrodes

Gallium oxide (Ga2O3) thin films were deposited on quartz substrates under different oxygen flow ratios (O2/[O2+Ar], 0%−5%) by radio-frequency (RF) magnetron sputtering technique followed by thermal annealing at 900 °C for 2 h under N2 atmosphere. The influence of the oxygen concentration on the structural and optical characteristics of Ga2O3 thin films was investigated. The Ga2O3 thin films prepared under an oxygen flow ratio of 1% exhibited optimum crystal quality and the lowest oxygen vacancy (VO) concentration according to X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) investigations. All as-prepared polycrystalline Ga2O3 thin film samples exhibited high average transmittance above 87.8% in the visible spectral region and the 0% and 1% thin films had optical bandgap energies of about 4.9 eV. We also fabricated metal−semiconductor−metal (MSM) photodetectors based on 1% Ga2O3 thin films by employing pairs of Ni−Ni symmetrical or Ni−Al asymmetrical interdigitated electrodes. The Ni−Ni photodetector had a high on/off current ratio (Ion/Ioff > 105), a responsivity of 88.7 mA/W, and specific detectivity of 4.81×1010 J at 10 V bias under ultraviolet light-C (UVC) illumination, and the Ni−Al photodetector exhibited self-driven behavior along with short rise and fall times (0.45 s and 0.69 s, respectively).

Photovoltaic performance of magnetron sputtered antimony selenide thin film solar cells buffered by cadmium sulfide and cadmium sulfide /zinc sulfide

Antimony selenide (Sb2Se3)-based thin-film solar cells have recently attracted worldwide attention as an abundant, low-cost, and efficient photovoltaic technology. The highest efficiencies recorded for Sb2Se3 solar cells have been obtained using cadmium sulfide (CdS) as a buffer layer. The Cd-included hybrid buffer layers could be one option to increase device efficiency through more effective usage of light. Therefore, in this work, the effect of single CdS and hybrid CdS/zinc sulfide (ZnS) buffer layers on the photovoltaic performance of Sb2Se3 thin-film solar cells has been investigated in detail. Sb2Se3 thin films have been deposited on molybdenum (Mo)-coated soda-lime glass (SLG) substrates by radio frequency magnetron sputtering technique followed by a post-heat treatment process. The morphological, and structural properties of Sb2Se3 thin films have been investigated by X-Ray Diffraction and Scanning Electron Microscopy. To compare the device performances of single CdS and hybrid CdS/ZnS buffered Sb2Se3 thin-film solar cells, SLG/Mo/Sb2Se3/CdS/ZnS/indium tin oxide (ITO) and SLG/Mo/Sb2Se3/CdS/ITO structures have been fabricated. The findings of this study have revealed a reduction in solar cells’ performance from η=3.93% for CdS buffer to η=0.13% for CdS/ZnS hybrid buffer. The change in the solar cell performance using the CdS/ZnS hybrid buffer has been discussed in detail.

Effect of Post-thermal Annealing on the Structural, Morphological, and Optical Properties of RF-sputtered In2S3 Thin Films

Indium sulfide films were deposited by radio frequency magnetron sputtering technique on soda lime glass substrate. The deposition was conducted at the temperature of 150 °C and prepared films were then thermally annealed under argon atmosphere at 350 °C and 450 °C for 30 min. The impact of post-thermal annealing treatment on the properties of the films was investigated. From X-ray diffraction analysis, the formation of the stable tetragonal β-In2S3 crystal structure was substantiated and revealed that the thermal annealing treatment at 450 °C improved the crystallization of the films. The change in surface topographies and morphologies of the films depending on the post-thermal annealing process were examined by atomic force microscopy and scanning electron microscopy techniques, respectively. The stoichiometric ratio of constituent elements in the films was obtained by elemental analysis and it was seen that the films had slightly sulfur (S) deficit composition. It was found that the concentration of S slightly increased with the thermal annealing process. The room temperature photoluminescence spectra revealed that the films included vacancies of sulfur (VS: donor) and indium (In) (VIn: acceptor), indium interstitial (Ini: donor) and oxygen (O) in vacancy of sulfur (OVs: acceptor) defects with strong and broad emission bands at around 1.70, 2.20, and 2.71 eV.

Detection of biofuel adulterants using an optical fiber-based refractive index sensor

This study presents a Lossy Mode Resonance (LMR) based on fiber optic sensor for detecting biofuel adulteration. Tin Oxide (SnO2), coated over the clad removed portion of the optical fiber using the Radio Frequency Magnetron sputtering technique, was utilized as the sensing layer. The fabricated sensor probe was analyzed with various concentrations of the analytes that include methanol in ethanol, ethanol in methanol, methanol in water, ethanol in water, water in methanol, and water in ethanol. The absorption spectra of the fabricated sensor probe revealed two LMR peaks namely, LMR1 and LMR2 that exhibited wavelength shift under varying concentration of the analytes. The maximum sensor responses for the above combinations of the analytes were 4.95%, 3.30%, 3.00%, 3.56%, 2.91% and 3.57%, respectively. The sensitivities of the sensor probe towards these analytes were 0.46 nm/vol%, 0.17 nm/vol%, 0.49 nm/vol%, 0.58 nm/vol%, 0.08 nm/vol%, and 0.4 nm/vol%, respectively. The real time sample were examined using metal oxides coated sensors. The result exhibits SnO2 coated probe is sensitive than other probes.

Physical properties of aluminum doped Zinc Oxide thin films and single wall carbon nanotubes bilayers with potential application in photovoltaics devices

A study of transparent thin films of Zinc Oxide doped with Aluminum (AZO) processed by sputtering with potentials application as substrate for single wall carbon nanotubes processing by spray-coating is discussed in this work. AZO Thin films have been deposited by radiofrequency magnetron sputtering technique at room temperature in high vacuum ambient and using an Argon atmosphere. The AZO thin films and the processed bilayers of Zinc Oxide: Aluminum/Single wall carbon nanotubes were characterized by scanning electron microscopy, Raman spectroscopy, x-ray diffraction, ultraviolet-visible spectrophotometry, stylus profilometry and four-terminal method for the electrical resistivity measurement. The feasibility of the Zinc Oxide doped with Aluminum thin films for its use as single wall Carbon Nanotubes substrate processed by a low-cost technique, with potential application in the configuration of photovoltaics devices is presented, analyzed and discussed as function of its electrical, morphological and optical properties through Haacke figure of merit quantification. A two-order reduction in resistivity values, average acceptable transmittance values (∼80%), and crystallinity expected for polycrystalline films were obtained for AZO/Single wall carbon nanotubes bilayers; although the homogeneity of the single wall carbon nanotubes distribution on AZO thin films processed by RF-Sputtering should be improved, the possible application as transparent electrode in a usual configuration of solar cells of AZO/Single wall carbon nanotubes can be performed.

Evaluation of Supercapacitor Properties of Radio Frequency Sputter Binder‐Free and Nanosandwich WO3/SiO2/WO3 Thin Film

Supercapacitors require efficient and environmentally friendly electrodes. This study investigates the promising potential of a tungsten oxide/silicon dioxide/tungsten oxide (WO3/SiO2/WO3) thin film on a Cu substrate as an alternative to conventional metal oxide flexible electrodes. Motivated by the need for enhanced energy storage capabilities, the WO3/SiO2/WO3 composite combines WO3 high specific capacitance and electrochemical stability of WO3 with improved mechanical durability and high surface area of SiO2, offering a synergistic solution to overcome electrode limitations. Utilizing the radio frequency magnetron sputtering technique, the WO3/SiO2/WO3 thin film is precisely deposited on a Cu flexible substrate without organic additives, conductive agents, binder chemicals, or substrate pretreatment. Electrochemical characterization reveals the film's pseudocapacitive behavior, facilitated by the SiO2 interlayer, enabling influential adjustment of electrolyte ions within the electrode structure. The obtained high specific capacitances at various scan rates and current densities demonstrate the potential of the thin film for supercapacitor applications. This research highlights the nanosandwich WO3/SiO2/WO3 thin film as a promising material for flexible energy storage and intelligent nanodevices, making it a noteworthy candidate for various flexible applications. The findings contribute to the development of efficient and environmentally friendly energy storage solutions.