Surasing Chaiyakun

Growth of silver nanoparticles by DC magnetron sputtering

Silver (Ag) nanoparticles are of great interest for many applications. However, their fabrications have been limited by the synthesis methods in which size, shape, and aggregation are still difficult to control. Here, we reported on using direct current (DC) magnetron sputtering for growing Ag nanoparticles on unheated substrates. Effects of sputtering condition on grain size of Ag nanoparticle were discussed. At constant sputtering current and deposition time, the average sizes of Ag nanoparticles were 5.9 ± 1.8, 5.4 ± 1.3, and 3.8 ± 0.7 nm for the target-substrate distances of 10, 15, and 20 cm, respectively. The morphology evolution from nanoparticles to wormlike networks was also reported. High-resolution transmission electron microscopy image represented clear lattice fringes of Ag nanoparticles with a d-spacing of 0.203 nm, corresponding to the (200) plane. The technique could be applied for growth of nanoparticles that were previously difficult to control over size and size uniformity.

Growth and characterization of nanostructured TiCrN films prepared by DC magnetron cosputtering

Nanostructured TiCrN films were grown on Si (100) wafers by reactive DC unbalanced magnetron cosputtering technique without external heating and voltage biasing to the substrates. The effects of Ti sputtering current on the chemical composition, chemical state, electronic structure, crystal structure, and morphology of the TiCrN films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM), respectively. The results showed that all prepared films were formed as an understoichiometric (Ti, Cr)N solid solution with the fcc B1 type phase. The films exhibited a nanostructure with a crystallite size of less than 14 nm. The deconvolution of XPS spectra revealed the chemical bonding between Ti, Cr, N, and O elements. The addition of Ti contents led to the decrease of valence electrons filled in the d conduction bands which result in the change of binding energy of electrons in core levels. The roughness of the films was found to increase with increasing ITi. The cross-sectional morphology of the films showed columnar structure with dome tops.

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.

Variation of Color in Zirconium Nitride Thin Films Prepared by Reactive DC Magnetron Sputtering

This study is to evaluate a color variation of the zirconium nitride thin film, prepared from deposition technique of different N2 flow rates, ranging from 0.0 to 3.0 sccm, whereas the Ar flow rate is fixed at 3 sccm. The thin film was deposited on an unheated silicon wafer (100) via a reactive DC magnetron sputtering. The deposition current and deposition time were 0.6 A and 15 minutes, respectively. In the study, colors of film were changed from silver, gold, dark brown, brown, purple, pink to blue, when N2 flow rate further increase. Interestingly, the results indicate that gold color occurs in a very small interval of N2 flow rate.

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.

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.

Structure and Properties of Zrtio4 Thin Films Prepared by Reactive Magnetron Co-Sputtering Without Heating

ZrTiO4 thin films were deposited by reactive dc magnetron co-sputtering method without heating. The crystal structure, surface morphology, thickness, optical and dielectric properties of the thin films were investigated. At sputtering currents above 2.0 A without heating ZrTiO4 thin film was crystallization of the orthorhombic phase (111). The values of refractive index were ranged between 2.01 and 2.23 (at 650 nm). The optical packing density values were ranged between 0.85 and 0.96. From this study, it was observed that the refractive index values were strongly dependent on packing densities. The high dielectric constant width decreases from 74.3 to 43.3 when sputtering current increases, which is higher than other research.

Growth and characterization of CrAlN thin film deposited by DC reactive co-sputtering

Chromium aluminium nitride (CrAlN) thin films were grown on Si wafers by DC reactive magnetron co-sputtering technique without external heating and biasing to the substrates. The effect of N2 gas flow rate on the structure of the as-deposited films was invested. Cr and Al metals were used as sputtering targets. The Cr and Al sputtering current were fixed at 300 mA. The sputtering gas (Ar) flow rate was fixed at 10 sccm and the reactive gas (N2) flow rate was varied from 2 sccm to 10 sccm. The crystal structure, thickness, roughness, microstructure, surface morphology, elemental composition and hardness were characterized by glancing angle X-ray diffraction (GAXRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and nanoindentation technique, respectively. The results showed that, all the as-deposited films were formed as a (Cr, Al)N solid solution. The as-deposited films exhibited a nanostructure with a crystallite size of less than 40 nm. The crystal size and lattice constant was in range of 17-33 nm and 3.998-4.165 Å, respectively. The film thickness and roughness decreased from 400 nm to 244 nm and 2.8 nm to 1.4 nm, respectively, with increasing the N2 gas flow rate. The elemental composition of the as-deposited films varied with the N2 gas flow rate. Cross section analysis by FE-SEM showed compact columnar and dense morphology as increasing the N2 gas flow rate. The film hardness was in range of 14.1-60.3 GPa.