Papers by Keyword: Thin Film

Abstract: A typical spin coating technique entails three steps: dispense, in which the resin fluid is applied to the substrate surface; high-speed spin, in which the fluid is thinned; and drying, in which extra solvents are removed from the resultant film. For the growth of thin films, an embedded system-based spin coating machine has been developed. The PIC microcontroller (PIC16f877A), which might be powered by a driver circuit to drive a spinning motor, controls the spin coating machine effectively. The temperature sensor is used to determine the temperature, while the proximity sensor is used to determine the motor's speed. Using a temperature sensor, the temperature has been kept between 30 and 40 degrees Celsius. The developed system will coat thin films in a micro level thickness by adjusting the spinning speed and controlling the system using PIC microcontroller. To test the reliability and repeatability of the machine, Zinc oxide (ZnO) was prepared with the sol-gel technique and deposited on the glass substrate using embedded system based spin coating machine. ZnO thin films were prepared at different pH and exhibited the fundamental reflections of (100), (002), (101), and (102) with the hexagonal wurtzite crystal structure. The structural studies of ZnO thin films using XRD analysis confirm the presence of ZnO particles in the prepared films. Also, it ensures the prepared ZnO thin film is pure and that no other impurities have been observed in the XRD pattern.

Abstract: A chemical bath deposition technique was used to create the transparent, finely adherent ZnS and Lanthanum doped ZnS thin films on a glass substrate. The films were obtained in a water bath with reaction solutions containing Zinc, Lanthanum precursors, and trisodium citrate as a complexing agent. The amorphous nature of the films was confirmed by an X-ray diffractometer and the porosity of the films was checked by field emission scanning electron microscope. The presence of Lanthanum in ZnS films was confirmed by EDS. To find the band gap UV-Visible spectroscopy analysis was carried out. The impurity phase and the Raman modes were recognized by Raman spectroscopy. Further studies on the water splitting and photocatalytic degradation of organic dyes using La-ZnS nanomaterials are underway in our laboratory.

Abstract: In this present work, Pristine and 10 at.% of In-doped ZrO₂thin films were deposited by spray pyrolysis technique at optimized substrate temperature [Ts=450°C]. The greater the proportion of Indium ion dopant, significantly influences the structural, optical, morphological, and electrical properties of deposit thin films. The deposited thin films were characterized with XRD, UV-Vis, PL, HR-TEM with EDAX, and I-V characterization Studies. The crystallinity of Zirconium dioxide thin film was improved and size of crystals were decreased by Indium ion substitution. Optical study revealed that the film's optical transmittance enhanced from 80.3 percent to 86.5% as a result of the dopant. The energy bandgap increased at 4.93eV - 4.57eV, systematically. HR-TEM studies show the homogeneous particle distribution and denser surface texture at 22nm and 19nm of average particle agglomerations. The study of PL emission shows an increase in intensity on the blue emission band with enriched crystalline quality. The conductivity of the ZrO₂ was higher affected by Indium ion may result in increased conductivity, with low resistivity property.

Abstract: Lead Sulphide, PbS thin films deposited on glass substrates by a chemical bath deposition method, which is a simple and easily controlled technique. The reactive substances used to obtain the PbS layers were (Pb(NO3)2), NaOH, Sc(NH2)2 and H2O for different dipping concentrations of lead nitrate, dipping times and temperatures. The films were structurally characterized by X-ray diffraction studies. The films are very adherent to the substrate and well crystallized according to the face centered cubic structure with the preferred orientation (1 1 1). The films were optically characterized by the transmission and reflectance spectrum, examined by a UV – VIS Spectrophotometer. In the infrared range, low transmittance and reflectance are detected (between 10% and 30%), while there is no transmittance or reflectance in the UV and visible regions. It can be seen from absorption spectra that absorption is stronger in the UV and UV-VIS region and gradually diminishes. Maximum absorption is observed in the visible and ultraviolet range, which indicates that the film prepared is of nanocrystalline. The band gap of PbS can be varied in the range of 0.41 to 2.71 eV, which is a significant material feature and opens the door to a new class of applications. The calculated band gap was determined to be between 1.88eV and 2.1eV.

Abstract: This paper presents the results of factorial experiment applied to optimize Matrix‑Assisted Pulsed Laser Evaporation (MAPLE) and Pulsed Laser Deposition (PLD) coating technologies used to improve the corrosion resistance of steels. MnTa₂O₆ pseudo-binary oxides and 5,10-(4-carboxy-phenyl)-15,20-(4-phenoxy-phenyl)-porphyrin was used for these experiments to obtained thin film coating system of hybrid nanostructures. Based on factorial experiments, correlations between the main technological parameters of the coating process (MAPLE laser energy E_MAPLE [mJ], PLD laser energy E_PLD [mJ]) and porphyrin concentration and the main related property of the coating system (corrosion protection factor) were determined. The base material used as substrate in the experiments was S235JR+C. Electrochemical measurements showed that by applying the appropriate parameters of the coating technologies, homogeneous layered sandwich thin films were obtained and corrosion rate was reduced by more than 7 times.

Abstract: This research focuses on the crucial task of identifying the viscous sublayer in improving wet cleaning processes. Computational fluid dynamics (CFD) is employed to manipulate fluid properties and process parameters for optimizing cleaning efficiency. The research findings encompass the evolution of thickness across the wafer radius, characterization of the wavy air-liquid interface, velocity profile within the liquid, and measurement of the viscous sublayer's thickness. Key findings highlight the significance of small-scale turbulent structures, the competition between Coriolis and viscous forces, and the successful utilization of CFD LES (Large Eddy Simulation) for quantifying and visualizing the viscous sublayer and eddy flow.

Abstract: Green or renewable energy is important to attain a sustainable low carbon economy and the use of hydrogen has been an alternative solution for the unreliable continuous supply of these energy sources. Solid oxide electrochemical cells is a promising technology for hydrogen generation in which the LSM-YSZ is one of the important component materials for this application. In this study, LSM-YSZ will be deposited on the YSZ substrate via screen-printing. Screen-printing is an easy and simple set-up that offers film quality control. Specifically, the study aimed to deposit a porous LSM-YSZ thin film, as well as to determine the effect of the particle size of the starting powders on the quality of the deposited film. Two synthesis methods for the powders were utilized before screen printing, the solid-state reaction (SSR) ball milling, and the glycine nitrate process (GNP). Results showed that a porous and even thin film with uniform distribution of LSM and YSZ was obtained after the screen printing. Moreover, the GNP powders produced a smaller particle size, a more porous morphology, and a thinner film when screen-printed compared to the SSR ball milled.

Abstract: Fabrication of Disperse Orange 3 thin film for photonics technology application has been carried out by using PVD method. The molecular structure of this film have been investigated by using FTIR and also by IRRAS methods. The optical properties have been investigated by UV-VIS measurement. In this paper the effect of molecular orientation and the molecular stcking/arrangement within the thin film were discussed.

Abstract: Indium gallium nitride / gallium nitride (InGaN/GaN) heterostructures were grown by using metal organic vapor deposition technique with four different growth temperatures (740 °C, 760 °C, 780 °C, and 800 °C). The structural properties and crystalline quality were investigated using high resolution X-ray diffraction (HRXRD) technique. XRD ω-2θ scan mode at GaN (002) diffraction plane was performed to assess the film’s quality. Through the simulation fitting, the indium composition and the thickness of the thin films were obtained. From the observation, an increase in the growth temperature resulted in higher intensity and smaller full-width at half maximum value of the InGaN (002) diffraction peak, which indicated improvement to the crystalline quality of the InGaN/GaN heterostructure. Moreover, the indium composition of the InGaN epilayer was found to decrease with an increase of the growth temperature due to the thermal decomposition of In-N bond and its re-evaporation from the growing surfaces.

Abstract: Monodispersed Ag nanorods were synthesized using a one-pot synthesis method. These Ag nanorods normally manifest dual surface plasmon resonance (SPR) peaks. This work presents a study of the variation of SPR peaks with variation in the shape of Ag nanorods. Shape variation was achieved through the degradation of a shape-controlling agent (PVP in this work) under white light irradiance with silica passivation to halt further shape variations. This paper also reports the growth & characterization of thin films of the synthesized rod-shaped silver nanoparticles on glass slides along with studies on band pass filter characteristics of the as-synthesized nanoparticles.