K. Joy

Bio: K. Joy is an academic researcher from Mar Ivanios College. The author has contributed to research in topics: Thin film & Band gap. The author has an hindex of 18, co-authored 47 publications receiving 979 citations.

Effect of annealing temperature on the structural and optical properties of zno thin films prepared by rf magnetron sputtering

Abstract: ZnO thin films were deposited on corning glass substrates by RF magnetron sputtering at room temperature. The dependence of crystal structure, morphology and optical properties on post-deposition annealing was investigated using XRD, AFM and UV–vis Spectrophotometer. The as-deposited films were amorphous in nature. Post-deposition annealing for 1 h in air caused an improvement in crystallinity with preferential orientation along (0 0 2) direction. Better crystallinity was observed at 673 K. Crystallite size increased from 16 to 27 nm as annealing temperature was increased from 473 to 873 K. It is evident from AFM analysis that rms roughness of the film annealed at 673 K is minimum indicating better optical quality. Optical measurements show a decrease in direct band gap from 3.289 (as deposited) to 3.25 eV when the annealing temperature was increased to 673 K. With further increase in temperature, band gap increases.

The electrical properties of polymer nanocomposites with carbon nanotube fillers

Abstract: The electrical properties of polymer nanocomposites containing a small amount of carbon nanotube (CNT) are remarkably superior to those of conventional electronic composites. Based on three-dimensional (3D) statistical percolation and 3D resistor network modeling, the electrical properties of CNT nanocomposites, at and after percolation, were successfully predicted in this work. The numerical analysis was also extended to investigate the effects of the aspect ratio, the electrical conductivity, the aggregation and the shape of CNTs on the electrical properties of the nanocomposites. A simple empirical model was also established based on present numerical simulations to predict the electrical conductivity in several electronic composites with various fillers. This investigation further highlighted the importance of theoretical and numerical analyses in the exploration of basic physical phenomena, such as percolation and conductivity in novel nanocomposites.

Nanocomposite Coatings: Preparation, Characterization, Properties, and Applications

Abstract: Incorporation of nanofillers into the organic coatings might enhance their barrier performance, by decreasing the porosity and zigzagging the diffusion path for deleterious species. Thus, the coatings containing nanofillers are expected to have significant barrier properties for corrosion protection and reduce the trend for the coating to blister or delaminate. On the other hand, high hardness could be obtained for metallic coatings by producing the hard nanocrystalline phases within a metallic matrix. This article presents a review on recent development of nanocomposite coatings, providing an overview of nanocomposite coatings in various aspects dealing with the classification, preparative method, the nanocomposite coating properties, and characterization methods. It covers potential applications in areas such as the anticorrosion, antiwear, superhydrophobic area, self-cleaning, antifouling/antibacterial area, and electronics. Finally, conclusion and future trends will be also reported.