Papers by Keyword: Thin Film

Abstract: The optical properties of CdZnS nanofilms are studied in this paper in relation to the deposition time. Deposition times ranged from 15 to 60 minutes for the CdZnS thin films, which had been developed on surface of glassy substrates. The other factors, such as reactant concentration, solution pH, and bath temperature, were held constant throughout the deposition process. The films were annealed at 200 °C for 120 minutes in a thermal furnace after the deposition process. Measurements of absorbance, transmission spectrum, and direct and indirect energy gaps were made using UV-VIS spectrophotometers. Transmittance in the 400-1000 nm range was 70-90 percent for all of the prepared films. With a wavelength of 600 nm and higher, transmittance was around 90%. CdZnS films have bandgap energies ranging from 2.4–2.15 eV for direct transitions and from 2.1–1.97 eV for indirect band gaps.

Abstract: In this study, the photovoltaic properties of zinc oxides are investigated. Different stoichiometries of zinc oxide can be made using vacuum deposition. Thermally evaporated zinc produces thin films of ZnO composed of orthorhombic and tetragonal phases that define the material's characteristics and performance. On-thermal plasma has removed a very thin layer from the surface of the thin film, known as non-thermal plasma, and made a surface cleanup. Measurements of the Atomic Force Microscope (AFM) show that the value of the granular volume rate increases when the duration of exposure to non-heat plasma increases. Measurements of the Atomic Force Microscope (AFM) show that there is an increase in thin film surface roughness values (Roughness, Sq), as well as the square root of the average roughness of the thin film surface (RMS), and this increase in roughness appears as the duration of exposure to non-thermal plasma increases.

Abstract: Praseodymium (Pr) doped (0.1 to 6 wt. %) nanostructured SnO₂ thin films are prepared via nebulizer assisted spray deposition process at a deposition temperature of 320 °C. The analyses show that the films grow in (110), (301) and (310) preferred orientations. The fabricated sensing films are exposed to LPG at 500 ppm concentration and at different operating temperatures. In 500 ppm of LPG, at an operating temperature of 350 °C, a commendable sensor response of 99 % with fast response time of 9 s and recovery time of 11 s is shown by 1wt.% Pr doped film, which is appreciable compared to pristine SnO₂ film. The sensor response reduces at lower operating temperatures. Microstructural investigations justify the gas sensing performance of 1 wt.% Pr doped SnO₂ thin film. Raman and photoluminescence studies give an insight into oxygen vacancies and trapped states that have a crucial influence on gas sensing.

Abstract: We study the crystal structure of carbon-doped Al-rich MnAl thin films deposited on Si substrates. The effects of carbon content and vacuum heat treatment parameters are studied. It is shown that the carbon content, in combination to heat treatment, allows to tailor structural phase transitions in the films. The main phases detected are Al₂Mn₃, pure Mn, and pure C. As carbon content increases, the amount of Al₂Mn₃ phase decreases and the content of pure crystallized Mn phase increases. In addition, it is shown that as the heat treatment temperature increases – up to 500 °C – the Al₂Mn₃ phase content increases, whereas a pure C phase appears at lower temperatures.

Abstract: The present article deals with synthesis of CdS thin films using cost effective chemical bath deposition method and study effect of annealing over the structural properties using X-ray diffraction pattern (XRD). The XRD pattern revealed shift in peak position and variation in intensity upon annealing at different temperatures; this may be attributed to annealing assisted modifications in composition of the thin films. The as deposited CdS thin films represents peaks corresponding to (002), (101), (111) and (110) which in case of annealed samples at 200 and 400oC get modified and slightly shifted with rising some new peaks corresponding to (200) and (001) respectively. The crystallite size of the CdS thin films upon annealing is observed to be increased this may be co-related to the fact energy induced grain growth.

Abstract: Zinc oxide (ZnO) thin films are synthesized by using modified successive ionic layer adsorption and reaction techniques (SILAR) on glass substrate at room temperature. These as deposited thin films are characterized for structural, compositional, surface morphology and optical characterizations using X-ray diffraction (XRD), energy dispersive X-ray absorption spectra analysis (EDAX), atomic force microscopy (AFM) and Uv-vis absorption spectroscopy. From XRD pattern; the low intensity peaks indicate that the films consist coarsely fine grains and/or amorphous in nature. The diffraction peaks observed at 2θ = 31.71 ̊, 36.27 ̊and 56.29 ̊ are attributed to (100), (101) and (110) planes having hexagonal phase while EDAX shows elemental traces for Zn and O. Surface morphology observed from the AFM corresponds granular shape evenly distributed over substrate surface.

Abstract: In the present work, pure copper ferrite (CuFe₂O₄) thin film has been grown on clean glass substrate by using the spray pyrolysis deposition technique. All the necessary parameters were optimized before the deposition. The deposited thin film was annealed at 500°C for 4 h and then cooled to room temperature. X-ray diffraction (XRD) technique was used to study the phase purity and crystal structure of the sample formed on the thin film. The analysis of the X-ray diffraction pattern reveals the formation of a single-phase cubic spinel structure. The lattice constant and other structural parameters calculated from XRD data are in good agreement with the reported data.

Abstract: This paper introduces a review of the use of gold nanoparticles (AuNPs) in the fabrication of optical fiber biosensors based on localized surface Plasmon resonance (LSPR) and Evanescent field absorption. The AuNPs have special properties, such as high surface/volume ratio, and intense light scattering/absorption, and stable structure. The main advantage of AuNPs in the application of the biosensor in the detection signal increasing, for especially low concentration analyses. Moreover, we illustrate some of the previous works in this field in the period from 2001-2021, which used optical fiber and AuNPs as a base in the development of various biosensors and all exhibited differently limits of detection, sensitivity, and good performances to its target detection.

Abstract: Nb₂O₅ has recently been considered as one of the oxides thin films that attracts a noticeable attraction by scientific prospective aspects. Its usefulness in a wide practical applications range such as in optoelectronic devices, optical coatings, catalysis, gas sensors, photocell, electrochromics, photoelectrodes, Ec devices, microelectronics and in the medical field paid researchers attention to synthesize it by various methods like sol.gel, electrodeposition, chemical vapor deposition etc. Among those, Pulsed laser deposition technique has achieved an effective improvements. In this paper, we aim to revise increasing significance of Nb₂O₅ supported by previous applications and a further possible future outlook.

Abstract: Microcrystalline cellulose (MCC) from bamboo is a natural biodegradable polymer that can be applied as barrier materials in the form of films. Bamboo contributes to 90% of the total mass of the dry weight comprised of cellulose, hemicellulose, and lignin. In this study, Gigantochloa albociliata (Buluh Madu) was chosen due to the fast-growing species, cheaper and abundance in Malaysia. This bamboo was undergone Kraft pulping process to get the pure cellulose and then continued with the acid hydrolysis process to produce microcrystalline cellulose (MCC). In this study, thin-film PLA/PBAT reinforced with microcrystalline cellulose derived from Gigantochloa albociliata were produced. PLA is high in strength and ductility, but it is brittle while PBAT is elastic and strong. Therefore, PBAT is a great candidate for PLA hardness. The thin film was characterized with XRD, DSC and TGA to compare the thin film from microcrystalline cellulose derived from bamboo (B-MCC) with the commercial microcrystalline cellulose (C-MCC). The C-MCC was used as reference material. From the results, B-MCC has the same crystallinity index as C-MCC with a value of 51.3%. It can be concluded that B-MCC is can be one of the alternatives for the microcrystalline cellulose due to the abundance of bamboo as fast-growing species. Furthermore, it exists naturally, has low cost, is biodegradable, is a low-density compound, and fits best in the field of renewability.