Nano Thin Films Research Articles

The Effect of Doping Zinc Oxide Thin Films With (0.5 wt. %) Carbon Nanotubes by Vacuum Evaporation

The study included the production of nano-thin films made of zinc oxide doped with carbon nanotubes (ZnO:CNTs) at a doping ratio of 0.5 wt%. The materials are applied onto glass substrates using the vacuum evaporation process. The structural characteristics of the thin films of undiluted and doped ZnO were assessed using X-ray diffraction (XRD). Additionally, the surface properties of the films were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The optical characteristics of the thin films were analyzed and described using UV-Vis spectroscopy. The ZnO thin films exhibited crystalline formations. The thin films exhibited significant orientations along the (100), (002), and (101) crystallographic planes, indicating their hexagonal phase structures. The crystal size of ZnO thin films exhibited a range of 30.87 nm to 19.96 nm after the process of doping. The study findings demonstrate that the addition of carbon nanotubes leads to an increase in the absorption ratio. Zinc-doped carbon nanotube thin films has features that make them suitable for many applications, such as gas detectors and UV detectors.

ZnS and CdS nano thin films – A comprehensive analysis of structural, morphology and optical properties for photovoltaic applications

The current study is on the deposition of Zinc Sulfide and Cadmium Sulfide thin films by chemical bath deposition (CBD) technique. The deposited films were annealed at 200 °C and 350 °C in vacuum system. The Structural, Surface morphology, elemental composition and Optic analysis were performed by XRD, SEM, EDX, PL and optical transmission spectra. The XRD confirmed the formation of ZnS and CdS which revealed a broad spectrum in the low 2θ region due to its amorphous behaviour. The average optical transmission spectrum of ZnS lies between 65 % and 80 % and CdS lies between 50 and 60 %. The optical band gap of both the annealed films was decreasing with increase in temperature. The higher optical transmittance observed from emission spectra of PL analysis can contribute better performance and proved that the annealed ZnS and CdS thin films are applicable for photovoltaic applications.

Multiobjective Optimization Strategy for Enhancing the Efficiency and Quality of Organic Thin-Film Manufacturing with Electrohydrodynamic Atomization Coating.

Electrohydrodynamic atomization coating technology is well-suited for micro-/nanoscale thin-film additive manufacturing. However, there are still some challenges in quality control and parameter adjustment during the coating process. Especially when coating on nonconductive and nonhydrophilic substrates, film quality and thickness uniformity are difficult to control. This paper proposes an optimization strategy for enhancing the efficiency and quality of thin-film manufacturing on nonconductive, nonhydrophilic glass substrates. In this paper, a visual inspection system was developed for in situ inspection and identification of droplet deposition states in the substrate surface. Then, the statistical relationship between the operating parameters and the quality of the deposition state was analyzed by response surface methodology. On this basis, machine learning models and intelligent recommendation frameworks for small data sets were developed to rapidly optimize operating parameters and improve the quality of thin-film coating. Optimization strategy developed by applying the principles of statistical modeling, analysis of variance, and global optimization are more efficient and less costly than traditional parameter screening methods. The experimental results show that optimum deposition quality can be obtained with the recommended operating parameters. And, validation results show a 12.8% improvement in film thickness uniformity. At the same time, no mura defects appeared on the thin-film surface. The proposed optimization strategy can improve the efficiency and quality of additive manufacturing of micro and nano thin films and is beneficial for advancing industrial applications of the electrohydrodynamic atomization coating.

Synthesized of gallium Nitride/PSi nano thin films using 532 nm wavelength by pulsed laser deposition technique

Synthesized of gallium Nitride/PSi nano thin films using 532 nm wavelength by pulsed laser deposition technique

Synthesis and Characterization Studies of Pure and Co Doped ZnO Nano Thin Films

General Background: Thin-film technology is pivotal in advancing modern optoelectronic devices due to its ability to tailor material properties at the nanoscale. Specific Background: Zinc oxide (ZnO) and cobalt oxide (CoO) are prominent materials in this field, with doping techniques such as cobalt incorporation offering potential enhancements in film properties. Knowledge Gap: The impact of cobalt doping on the structural and optical properties of ZnO thin films remains inadequately explored, particularly concerning varying doping concentrations. Aims: Aims to elucidate the effects of cobalt doping on ZnO thin films' structural and optical characteristics, with concentrations of Zn0.6Co0.4O and Zn0.8Co0.2O compared to pure ZnO and CoO films. Results: Thin films were prepared via spin coating on glass substrates at 3000 rpm for 30 seconds. X-ray diffraction analysis revealed that pure ZnO films possess a hexagonal polycrystalline structure, whereas CoO films exhibit a cubic structure. Doping with cobalt resulted in a decrease in peak intensity at the (111) orientation and an increase in grain size. Optical measurements indicated enhanced transmittance and modified absorbance spectra with increased cobalt content, showing maximum absorbance at short wavelengths and diminished values in the visible region. Reflectivity increased with photon energy before decreasing at higher energies. Novelty: Cobalt doping significantly alters both structural and optical properties of ZnO films, with distinct changes in lattice constants, grain size, and optical behavior, suggesting a potential route for optimizing ZnO-based materials. Implications: Cobalt-doped ZnO films hold promise for improved performance in optoelectronic applications, such as solar cells and sensors, necessitating further research into diverse doping strategies to fully harness their technological potential. Highlights: Cobalt doping alters ZnO thin films' structural and optical properties. Spin coating method used at 3000 rpm for 30 seconds. Enhanced optical properties suitable for optoelectronic applications. Keywords: Thin films, Zinc oxide, Cobalt doping, Optical properties, X-ray diffraction

Upcycling spent Ni–Cd battery for selective synthesis of nanoparticles to harness into electro-conductive thin films: An eco-friendly approach for e-waste management

Inspired by Sustainable Development Goal-12 (responsible consumption and production) to reduce e-waste, an environment friendly extraction of Cd, Ni and Co from Ni–Cd spent batteries have been reported here using ammonium chloride as a chlorinating agent for the first time. Multiple parameters i.e. dose of chlorinating agent, roasting time, and temperature has been optimized that resulted in extraction of 99.93 % Cd, 90.1 % Ni and 84.81 % Co. Metal enriched leachate was then subjected to unique precipitation steps that resulted in synthesis of Cd nanoparticles, Co3O4·NiO composite nanoparticles, and NiO nanoparticles, characterized through XRD and FESEM-EDX. Synthesized nanoparticles were further employed in the fabrication of electro-conductive nano thin films via Layer by Layer (LbL) technique. Film buildup of six novel architectures was monitored using an Ellipsometer. Homogenous film growth was tailored by optimizing ratio, concentration and dipping time of nanoparticles and polymer solutions. Conductivity studies revealed that imbedding synthesized nanoparticles impart significant conductive behavior in thin films with maximum conductivity of 1.8 × 10−4 S/cm, in addition to exhibiting appreciable resistance against 0.1 M HCl, 0.1 M NaOH and acetone. Contact angle and AFM images revealed that the films were slightly wettable and homogenous respectively. Conclusively not only Cd, Ni and Co were successfully recycled from Ni–Cd spent batteries employing greener technique but were also harnessed into robust nano-thin films with focus towards electro-conductivity based applications.

P‐238: Late‐News Poster: Novel Method for Fast Assessment of Surface Conditions of Nano‐Thin Films

In this study, we developed a method for measuring and evaluating the surface of Nano thin films used for displays. In this device, the contact angle of the surface is measured by dividing the entire area within 10″ by the desired ratio, and the Nano thin film state of the surface is verified by obtaining surface energy at high speed.

Hydrophobic Coatings with Charge Permeability via Plasma Deposition of Long-Chain Perfluorocarbons.

Hydrophobization of nanotextured catalyst materials is a promising route to enhance the yield of N2 and CO2 conversion into green fuels. However, these applications require a hydrophobic coating to not only promote air trapping but also allow charge transfer at the electrode-electrolyte interface. In this work, nano thin films with thicknesses as low as 7 nm were deposited from the plasma phase of perfluorohexene, perfluorodecene, and perfluorooctane (PFO) precursors using a mild vacuum and gentle powers. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) characterization reveal that the resulting films are conformal and hydrophobic thanks to a good retention of CF2 and CF3 moieties. The PFO films exhibited the highest water contact angle and achieved superhydrophobic states when deposited on top of re-entrant nano features, an indication of successful air trapping. Electrochemical studies further demonstrated that the plasma-deposited PFO films allow charge transfer but could only sustain repeated cyclic voltammetry cycles without losing their hydrophobicity when deposited under optimal conditions. This result indicates that plasma deposition could become a viable route for the hydrophobization of electrocatalysts required to enhance the yield of poorly soluble gas reduction reactions.

Thermally controlled band gap tuning in CuO nano thin films for optoelectronic applications

Thermally controlled band gap tuning in CuO nano thin films for optoelectronic applications

Effect of annealing temperature on bismuth vanadate nano thin films for solar cell applications

Bismuth vanadate (BiVO4) has been used as the photoanode electrodes in ferroelectric solar cells owing to its unique combination of properties: a narrow bandgap among ferroelectrics, economic viability, negative conduction band edge, and remarkable stability. The present work explores the fabrication and characterization of BiVO4 thin films prepared via spin coating, with a specific focus on elucidating the influence of the annealing temperature (400–550 °C) on their structural, optical, and photovoltaic properties. From X-ray diffraction (XRD) analysis, it is observed that higher annealing temperatures have promoted the formation of larger grains, enhanced crystallinity, and induced a preferred crystal orientation characteristic of the monoclinic scheelite structure. Tauc plot analysis shows the dependence of the optical band gap on the annealing temperature for BiVO4 thin films. The band gap values have decreased slightly from 2.50 eV at 400 °C to 2.44 eV at 550 °C. This is indicated by the slightly narrowed bandgap, which influences the structure of the material or defect states at higher annealing temperatures. A narrower bandgap allows for the absorption of lower-energy light, potentially improving the light absorption efficiency of BiVO4 thin films in photoanode applications. The influence of annealing temperature on BiVO₄ thin film solar cell performance was investigated further through the analysis of open-circuit voltage (Voc), short-circuit current (Isc) and power conversion efficiency.

Nonlinear optical properties of zinc oxide thin films

This study reports the influence of deposition temperature (573 K-773 K) on the microstructural, linear and nonlinear optical properties of zinc oxide nano thin films synthesized using the chemical spray pyrolysis method. Synthesized films are polycrystalline, exhibiting a dominant (101) orientation, for which the crystallite size is found to increase with deposition temperature up to 723 K followed by a decrease. Concurrently, the deposit prepared at 723 K showed improved electrical properties, i.e. higher charge carrier concentration and mobility. Optical studies reveal increased transmittance in the visible region and a gradual increase of optical bandgap with deposition temperature. The photoluminescence studies show a near-white light emission for all thin films, however, the density of defect states was comparatively higher for thin films deposited at lower temperatures. A saturable absorption behaviour was observed due to the presence of defects. The thin films show a negative refractive index with self-defocusing phenomena. The total nonlinear susceptibility is found to decrease with increasing deposition temperature, and the solution-processed functional thin films thus have potential implications for nonlinear optical applications such as nonlinear optical switching, optical memory management, and saturable absorbers.

Wafer-Scale epitaxial molybdenum disulfide ultrathin film on sapphire prepared by low-energy reactive magnetron sputtering

Molybdenum disulfide, a two-dimensional semiconductor, has found broad applications in various functional devices. Currently, developing a reliable method for growing wafer-scale monolayer molybdenum disulfide presents a significant challenge in its integration into the contemporary semiconductor industry. This study employed low-energy reactive magnetron sputtering with hydrogen disulfide gas to deposit wafer-scale epitaxial few-layer and monolayer molybdenum disulfide on c-sapphire substrates. The epitaxial molybdenum disulfide nano-thin film was examined using scanning nano-probe X-ray diffraction technique, revealing a single grain size of no less than 50 × 50 μm2. Furthermore, the growth of monolayer molybdenum disulfide on both c-sapphire and thermal silicon oxide substrates was verified through Raman microscope. Measurements of photoluminescence and X-ray photoelectron spectroscopy also confirmed the monolayer state of the sputtered nano-thin films. This study suggests that reactive magnetron sputtering with hydrogen disulfide gas offers a cost-effective, scalable method for growing large-area molybdenum disulfide nano-thin films, thereby holding significant potential for practical semiconductor industrial applications.

ZnO based 0-3D diverse nano-architectures, films and coatings for biomedical applications.

Thin-film nano-architecting is a promising approach that controls the properties of nanoscale surfaces to increase their interdisciplinary applications in a variety of fields. In this context, zinc oxide (ZnO)-based various nano-architectures (0-3D) such as quantum dots, nanorods/nanotubes, nanothin films, tetrapods, nanoflowers, hollow structures, etc. have been extensively researched by the scientific community in the past decade. Owing to its unique surface charge transport properties, optoelectronic properties and reported biomedical applications, ZnO has been considered as one of the most important futuristic bio-nanomaterials. This review is focused on the design/synthesis and engineering of 0-3D nano-architecture ZnO-based thin films and coatings with tunable characteristics for multifunctional biomedical applications. Although ZnO has been extensively researched, ZnO thin films composed of 0-3D nanoarchitectures with promising thin film device bio-nanotechnology applications have rarely been reviewed. The current review focuses on important details about the technologies used to make ZnO-based thin films, as well as the customization of properties related to bioactivities, characterization, and device fabrication for modern biomedical uses that are relevant. It features biosensing, tissue engineering/wound healing, antibacterial, antiviral, and anticancer activity, as well as biomedical diagnosis and therapy with an emphasis on a better understanding of the mechanisms of action. Eventually, key issues, experimental parameters and factors, open challenges, etc. in thin film device fabrications and applications, and future prospects will be discussed, followed by a summary and conclusion.

Efficient inverse design of optical multilayer nano-thin films using neural network principles: backpropagation and gradient descent.

Optical multilayer thin films have a wide range of applications due to their ability to manipulate transmissive or reflective wavelengths by adjusting the thickness of composed layers, enabling diverse uses. Although their light weight, flexible nature and ease of fabrication position them as promising components for future devices, determining their optimal layer thickness for the desired functionality demands extensive simulations, leading to inefficient utilization of computational resources and time. To overcome these challenges, inverse design methods, leveraging machine learning and deep learning, are being explored. However, these methods necessitate learning processes, despite the presence of well-established formulas that elucidate these phenomena. Furthermore, deriving accurate answers for conditions not included in the learning process proves to be challenging. This paper introduces an innovative inverse design approach that utilizes the backpropagation of a networked transfer matrix, effectively explaining the characteristics of optical multilayer thin films. By exploiting the chain rule of the network, this method calculates gradients to discern how each layer thickness influences the outcomes. Consequently, the optimal thickness is determined without the need for an additional learning process. Mathematical elucidation of the operational principle of this approach is precisely described. Optimization of computing resource utilization through network configuration reduces the calculation time compared to conventional methods. The efficacy of this method is demonstrated through its application in the inverse design of transmissive and reflective films, verifying its potential for enhancing efficiency and accuracy in optical multilayer thin-film design and manufacturing processes.

Environmental sustainability of FO membrane separation applications – Bibliometric analysis and state-of-the-art review

Water treatment, product concentration, and resource recovery are few examples of the many areas where the economic promise of osmotic driven membrane separation remains unrealized. The most futuristic and sustainable, osmotic driven membrane separation process which works with-out any external hydraulic energy is forward osmosis (FO) process. This study comprises two parts first is of bibliometric analysis which helps to identify and analyze the current research trend in osmotic membrane filtration technique, and are represented along with nodal network visualization. Desalination and wastewater treatment seem to be the major application of FO technology followed by fertigation, algal dewatering, pharmaceutical and textile industries. The second part is the literature review on major applications of forward osmotic technique shortlisted from bibliometric analysis, which includes recent developments in FO research. An application based critical analysis on thin film nano composite membrane, draw solutes, nano particles for membrane modifications and hybrid FO units were performed. Analysing literatures from 2005 to 2022, this study pinpoints potential applications, future prospects and existing challenges in Forward Osmosis (FO), for the successful implementation of scale-up.

Structural, Optical, and Electrical Characteristics of Titanium Dioxide Thin Films Prepared by Pulsed Laser Deposition

In this research, the Pulsed Laser Deposition (PLD) technique was used, and the operating frequency of the laser was tuned to a double frequency. This was done in order to construct nano-thin films of titanium oxide (TiO2). An Nd-YAG laser with a wavelength of 1064 nm, pulse frequency of 6 Hz, and laser energy of 700, 800, and 900 mJ were used on glass and Si (p-type) substrates of different thicknesses. Then, the TiO2 films were annealed for 2 hours at a temperature of 400 °C. UV-Vis spectra revealed that TiO2 has strong UV absorption, as well as a large energy gap (2.9, 3.06, and 3.3) eV for energy levels (700, 800, and 900) mJ in contrast. In addition, FESEM analysis showed a granular morphology that showed a tendency for fragmentation into smaller particles with the growth of the thickness of the sample. The thickness of the thin films was determined using the FESEM cross-section, and the results showed that the thicknesses were 278.01, 1630.53, and 2579.66 nm for TiO2 at laser energy of 700, 800, and 900 mJ, respectively. As the laser energy increased, the results showed an increase in the thickness of the thin film. In addition, the absorbance increased while the transmittance decreased with increasing thin film thickness. In terms of the electrical properties of the cell, we found that the efficiency of the annealed cell was significantly increased compared to that of the unannealed cell.

Effect of ambient argon pressure on the structural, optical and electrical properties of non-crystalline Se85Te3Bi12 nano-thin films

In this research work, we have synthesized non-crystalline Se85Te3Bi12 chalcogenide glasses by conventional melt quenching technique. The differential scanning calorimetry measurement of the synthesized specimen was done to confirm the glassy as well as non-crystalline nature of the bulk Se85Te3Bi12 alloy. The nano-thin films of thickness 30 nm of the synthesized sample at two different ambient argon pressures (1 Torr and 3 Torr) were made using the physical vapor condensation technique at a constant substrate temperature of 77 K using liquid nitrogen. The non-appearance of prominent peaks in the high-resolution x-ray diffractometer profile confirmed the non-crystalline nature of synthesized nano-thin films. The morphological analysis of the prepared nano-thin films using Field emission scanning electron microscopy confirmed the nanochalcogenide having particle size ranges from 30–90 nm. The Fourier transform infrared (FTIR) spectroscopy suggests the presence of moisture and carbon impurities in the prepared nano-thin films. The broad optical transmission shadow observed in the FTIR results is an essential requirement for new-generation IR systems. Based on UV-visible spectroscopy, optical parameters such as optical absorption coefficients, Urbach energy, optical band gaps, Tauc’s parameter and extinction coefficients were measured for synthesized Se85Te3Bi12 nano-thin films. The value of absorption coefficients, Tauc’s parameters, optical band gap and extinction coefficients increases with the increase of ambient argon pressure. The outcome of these studies recommends that these materials can be a preeminent candidate for photovoltaic applications. Photoluminescence spectroscopy results are accredited to the accumulation of non-crystalline nanochalcogenide particles on the substrates. DC conductivity measurements further confirm the semiconducting nature of the nanochalcogenide Se85Te3Bi12 thin films.

Optimizing physico-chemical properties of hierarchical ZnO/TiO2 nano-film by the novel heating method for photocatalytic degradation of antibiotics and dye

The design of semiconductor catalysts with excellent photocatalytic properties, stability, recyclability, and good separation for the treatment of polluted water is still challenging. In this paper, the ZnO/TiO2 nano-thin films were fabricated using the magnetron sputtering technique and then heating the underlying ZnO layer and the upper TiO2 layer for their respective optimal heating time, i. e. heating ZnO for 3 h and heating TiO2 for 2 h. The as-prepared films were characterized. The results show that the preferred growth of TiO2 grains along the [001] axis, relatively large specific surface area, and increased amounts of surface oxygen vacancies (OVs) were induced to the heterojunction catalysts through this optimized heating strategy, which boosts the photocatalytic activity of ZnO/TiO2 nano-film. The degradation experiment inndicates that the ciprofloxacin (CIP) removal efficiency can reach 97.3% in 2 h duration, which was higher than that of the samples annealed for the same periods. Meanwhile, the prepared ZnO/TiO2 photocatalytic film exhibited favorable stability of 95.5% degradation efficiency after the fourth run and general applicability for the photodegradation of various contantains, whih removed 99.5% of ofloxacin (OFX) and 77.6% of tetracycline (TC) in 2 h and 94.1% of Rhodamine B (RhB) in 1 h. This work is expected to yields a novel insight into the production of heterojunction photocatalysts with excellen ability for photocatalytic degradation of pollutants in the practical industry.

Photoluminescence and third-order nonlinear optical limiting properties of Sn1-xNdxO2 thin films deposited via spray pyrolysis

In the present work, spray pyrolysis method was adopted to synthesis nano thin films of Sn1-xNdxO2 (x = 0.01 to 0.1) possessing tetragonal structure with (1 1 0) plane orientation. Nd doping reduced the overall crystallinity of the films, however Sn0.92Nd0.08O2 film showed crystallite size of 18.7 nm, similar to that of the pure film. The morphology changed to distinct grains at lower doping concentration, beyond which a fibrous nature evolved but again changed to smaller grains with further increase in the doping. The oxidation states of the constituent elements were confirmed using XPS. The transmittance of the films reduced due to incorporation of Nd ions. A decrease in the energy band gap was also noticed in the films following dopant addition. The PL emissions corresponding to the Nd ion transitions was found in the NIR region resulting from internal 4f-shell transitions of Nd3+ ions. Other defect related emissions like the one from oxygen vacancies also showed up in the UV and visible wavelength regions, which were responsible for a near white light emission. The third-order optical nonlinearity of the films was confirmed using the Z-scan technique. All the Sn1-xNdxO2 films till 8 at. % of doping showed reverse saturable absorption. The highest and lowest nonlinear absorption coefficient was exhibited by Sn0.92Nd0.08O2 and Sn0.98Nd0.02O2 films, respectively. Depending on the Nd concentration, the films either showed self-focusing or self-defocusing behavior and influenced the nonlinear refractive indices of the films. The least optical limiting values among the doped films was obtained in the range of 1.73 kJ/cm2 for Sn0.92Nd0.08O2 films.

A Review of Different Types of Solar Cell Materials Employed in Bifacial Solar Photovoltaic Panel

Conventionally accessible silicon solar cells experience two major drawbacks, such as reduced efficiency and increased fabrication costs. The prospects for the reduction in the cost of the photovoltaic form of energy conversion are bifacial solar cells. Bifacial solar cells show potential opportunity in reducing the cost of solar energy conversion when analyzed with respect to monofacial cells. The bifacial solar cells exploit sunlight occurrence on both sides of the cell more efficiently. Bifacial-based solar photovoltaic (PV) is a technology that increases the generation of electrical energy per square meter of PV module through the utilization of light absorption from the albedo. This technology can generally be categorized based on the type of solar cell material and the fabrication technique. PV devices are classified as a silicon-based, thin film, organic, and advanced nano PV. This paper takes a second look at some recent initiatives and significant issues in enhancing the efficiency of bifacial solar cells from material sciences and chemical composition aspects. From this review, it is concluded that screen-printed solar cells have produced a maximum efficiency of 22%. Additionally, triode structure single-crystalline cells produced a maximum front side efficiency of 21.3% and rear side efficiency of 19.8%. Considering the recycling of solar panels, organic solar panels can be developed.