Nirun Witit-Anun

Functionalization of Au Nanoparticles on ZnO Nanorods through Low-Temperature Synthesis

Hybrid nanomaterials exhibit multi-functionalities, which is synergy or enhanced physical and optical properties over their single components with promising potentials for various applications in dye-sensitized solar cell and photocatalytic materials. In this present research, the Au nanoparticles were prepared at HAuCl4 concentration of 0.5 mM on ZnO nanorod templates and silicon wafer substrate by hydrothermal reaction process. The prepared samples were investigated the crystal structure, chemical composition and morphologies by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FESEM), respectively. The XRD results shown that ZnO was preferred orientation along the c-axis (002). The FE-SEM images indicated to the difference of size-Au NPs decorated on ZnO nanorods and silicon wafer. The relationship between the surface area and the size of Au NPs of the prepared samples was investigated and possible growing mechanism of Au NPs on ZnO nanorods templates will be discussed.

Characterization of ZrN Thin Films Deposited by Reactive DC Magnetron Sputtering

In the past decade, many transition metal nitride thin films, especially titanium nitride (TiN) and zirconium nitride (ZrN), have been widely used as hard coatings, decorative coatings, diffusion barriers in IC technology and heat mirrors, as a result of their attractive properties of high hardness, corrosion resistance, thermal stability and electrical resistivity [1-4]. However, the ZrN films have shown significant performance regarding to its higher hardness, better corrosion resistance, lower electrical resistivity and warmer golden colour compared to those of the TiN films. ZrN films have shown significant performance advantages over TiN films [5-.

Effect of Sputtering Power on Structural and Optical Properties of AlN Thin Film Deposited by Reactive DC Sputtering Technique

Aluminum nitride (AlN) thin films have been deposited on the glass slide and Si-wafer by reactive DC magnetron sputtering technique at different sputtering power. The as-deposited films have been characterized by grazing-incidence X-ray diffraction (GIXRD), atomic force microscopy (AFM) and optical transmittance, respectively. The results show that the as-deposited films were transparent and have high transmittance in visible regions. The crystal structure from XRD results show that the as-deposited films are amorphous with low sputtering power and turn to crystal structure with high sputtering power, which showed orientation of AlN structure corresponding to the AlN(1 0 0), AlN(1 0 1) and AlN(1 1 0). The roughness values and the films thickness from AFM was varied from 0.4 nm to 3.9 nm and 199 nm to 905 nm, respectively. The optical constants namely the refractive index n and the extinction coefficient k, were determined from transmittance spectrum in the visible regions by using envelope method. For 500 nm, n and k, were in the range of 1.8 2.0 and 0.014 0.004 respectively.

Effect of Ti Sputtering Current on Structure of TiCrN Thin Films Prepared by Reactive DC Magnetron Co-Sputtering

Titanium chromium nitride (TiCrN) thin films were deposited by reactive DC magnetron co-sputtering. The effect of Ti sputtering current (ITi) on the structure of the TiCrN thin films were investigated. The crystal structure, microstructure, thickness, roughness and elemental composition were characterized by glancing angle X-ray diffraction (GAXRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and energy dispersive X-ray spectroscopy (EDS) technique, respectively. The results showed that, all the as-deposited films were formed as a (Ti,Cr)N solid solution. The as-deposited films exhibited a nanostructure with a crystallite size of less than 40 nm. The crystal size decreased from 39.9 nm to 33.5 nm, while the lattice constants increased from 4.139 Å to 4.162 Å, with increasing of the Ti sputtering current. The film thickness and roughness were found to increase from 397 nm to 615 nm and 3.7 nm to 6.3 nm, respectively, with increasing of the Ti sputtering current. The composition of the as-deposited films varied with the Ti sputtering current. Cross section analysis by FE-SEM showed compact columnar and dense morphology as a result of increasing the Ti sputtering current.

Characterization and Analyzation of Chitosan from Anadara granosa Shell

This research work aims at characterize and analysis the physical and chemical properties of chitosan which derived from the Anadara granosa Shell. The physical and chemical properties have been also discussed in detail with X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy and Energy Dispersive X-Ray Fluorescence (EDXRF). The result showed that the XRD pattern indicated the Anadara granosa shell have crystalline structure of CaCO3 in Aragonite phase, while chitosan powder which extract from Anadara granosa shell has amorphous-crystalline structure. Another that, FTIR results confirmed the deeply formation of intermolecular bonding between the functional groups of the sample which the spectrum of FTIR indicate that the characteristic feature of Aragonite phase with the band of FTIR at ~1083 while the band at ~1653 were agree with chitosan polysaccharide. In addition, the EDXRF result were indicated that the concentrations of organic compounds in chitosan which extract from Anadara granosa shell have concentration is 33.581Wt% while the Anadara granosa shell have 0.033 Wt%. For Calcium (Ca) element the chitosan powder have concentration is 66.157 Wt% while the Anadara granosa shell have 99.850 Wt%.

Effect of Oxygen Partial Pressure on the Morphological Properties and the Photocatalytic Activities of Titania Thin Films on Unheated Substrates by Sputtering Deposition Method

Titania (TiO2) thin films have been deposited using d.c. reactive unbalance magnetron sputtering on unheated substrate by various different oxygen partial pressures while working pressure and sputtering power were kept constant. A pure metallic titanium disk was used for sputtering target in atmospheric of the mixture gases between argon and oxygen. The X-ray diffraction (XRD) and atomic force microscopy (AFM) were used for characterization of characteristics structure and surface morphologies of the films, respectively. The optical transmission of the films were measured by spectrophotometer. The photocatalytic activities of the films were investigated from measurement of methylene blue degradation by using absorbance value after UV irradiation for 6 hr. The results show that the crystalline structures of the films showed the presence of single-anatase phase and mixed-anatase/rutile phase of TiO2 thin films. The surface morphology and photocatalytic activities of the films depend on oxygen partial pressure that grains size, surface roughness and thickness of the films were deceased when increasing oxygen partial pressure due to poisoning phenomenon and the high reactive gases. In addition, it was found that all TiO2 thin films were deposited by different oxygen partial pressure exhibit a good transparentness. Moreover, it was found that the TiO2 thin films deposited by used low oxygen partial pressure and single-anatase phase exhibited the best photocatalytic activity.

Comparison of Nanocrystalline TiO2 Films Prepared on Unheated Substrates Using Single- and Dual-Cathode DC Unbalanced Magnetron Sputtering Systems

Titanium dioxide (TiO2) films were deposited on unheated Si(100) wafers by single- and dual-cathode dc unbalanced magnetron sputtering. Each cathode was specially designed with a high magnetic field strength. The effect of the radial distance from the center of the coating cathode on the film structures was investigated. For the substrate placed at the center of the coating cathode, it was found that the TiO2 films deposited by dual-cathode sputtering exhibit rutile with higher crystallinity than films deposited by single-cathode sputtering. At various radial distance from the center to 6 cm to the left and light of the center, mixed phases of rutile and anatase were observed on TiO2 films deposited using both single- and dual-cathode sputtering systems. Furthermore, in the case of using dual-cathode, crystalline TiO2 films were obtained for a longer range to the left of the center than to the right owing to the higher magnetic field strength.

Characterization of Anatase and Rutile TiO2 Thin Films Deposited by Two Cathodes Sputtering System

Titanium dioxide, TiO2, thin films were deposited on unheated Si (100) wafers by two cathodes sputtering system. However, during the deposition of TiO2 films only one cathode was used. A pure metallic titanium was used as a sputtering target. Argon and oxygen were used as sputtered gas and reactive gas, respectively. TiO2 films were deposited at the argon and oxygen ratio of 1:4 and a total pressure of 5.0 x 10-3 mbar. The distance between the target and the center point of substrate was 12 cm. For each deposition of TiO2 films, the position of substrate was changed every 2 cm on the radial position of the cathode. The deposition time for each deposition was 60 min. The films were characterized by X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). The XRD results and TEM images show that the crystalline rutile TiO2 films can be successfully deposited on an unheated substrate.

The Influence of Total and Oxygen Partial Pressures on Structure and Hydrophilic Property of TiO2 Thin Films Deposited by Reactive DC Magnetron Sputtering

TiO2 thin films have been deposited by reactive DC magnetron sputtering technique to study the effect of total pressure and oxygen partial pressure on structure and hydrophilic properties. The crystal structure and hydrophilic property was measured by XRD and contact angle meter, respectively. The results showed that the films were composed of pure rutile and mixed of anatase/rutile structure dependent on the total pressure and oxygen partial pressure. It was found that all films can perform hydrophilic property. In case of high total pressure, the films showed superhydrophilic property, whereas the films deposited under various oxygen partial pressures with fixed total pressure were all films exhibit superhydrophilic property.

Structural Characterization of Reactive DC Magnetron Co-Sputtered Nanocrystalline CrAlN Thin Film

Nanocrystalline CrAlN thin films were deposited on silicon substrates by reactive DC magnetron co-sputtering technique. The effect of deposition time on crystal structure, chemical composition, thickness, microstructure and hardness of the thin films were characterized by XRD, EDS, AFM and FE-SEM and Nanoindentation, respectively. The as-deposited films were formed as a (Cr,Al)N solid solution with (111), (200) and (220) plane. The lattice constants were in range of 3.9916 - 4.0455 Å. The as-deposited films exhibited a nanostructure with a crystallite size in range of 15-35 nm. The thickness and roughness increased from 197 nm to 998 nm and 1.6 nm to 8.1 nm, respectively, with increasing the deposition time. The chemical composition of the films varied with the deposition time. The cross section analysis by FE-SEM showed columnar structure and dense morphology. The film hardness decreased from 39 GPa to 25 GPa with increasing the deposition time and crystallite size.