Rosniza Hussin

Fabrication of Multilayer ZnO/TiO2/ZnO Thin Films with Enhancement of Optical Properties by Atomic Layer Deposition (ALD)

Atomic layer deposition (ALD) is a precision growth technique that is able to deposit either amorphous or epitaxial layer on a wide range of substrates. Multilayer thin films have been widely studied because their properties are different from those of bulk materials constituents owing to the two-dimensional films and high density of interfaces. Multilayer nanostructured thin films were fabricated on silicon and glass substrates by ALD. The optical and electrical of multilayer ZnO/TiO2/ZnO films were investigated. The microstructure compositions and surface morphology of these multilayer films were analyzed by X-ray diffraction (XRD), Atomic force microscope (AFM) and Scanning electron microscope (SEM). The optical properties were characterized using photoluminescence (PL) and UV-VIS spectroscopy. XRD patterns confirmed that ZnO with wutrtize crystal structure and TiO2 with anatase structure were presented. The degree of crystallinity of multilayer thin films has been improved through the deposition of ZnO. The intensity of UV luminescence of the multilayer has increased as compared to the single layer TiO2 and bilayer ZnO/TiO2. The multilayer ZnO/TiO2/ZnO has high transmittance (above 80%) in visible region. All the result suggested that the use of multilayer thin films effectively enhanced the quality of films crystallinity and optical properties as compared to single layer ZnO and bilayer ZnO/TiO2.

Effect of Temperature on TiO2/ZnO Nanostructure Thin Films

TiO2/ZnO nanostructured thin films were grown using sol-gel route. The nanostructured thin films were deposited by dip coating method on glass substrates and calcined at different temperatures (400°C, 500°C, and 600°C). The thin films were characterized using X-Ray Diffraction method (XRD), Atomic Force Microscope (AFM), and Ultraviolet Visible Spectroscopy (UV-Vis). The XRD pattern showed that the crystallinity of the calcined thin films had improved when the calcination temperature was increased. According to AFM observation and analysis, surface roughness of the thin films controllable via growth condition. While the transmittance percentage of ultraviolet by Titanium Dioxide (TiO2) thin films through UV-Vis could be improved by combination with Zinc Oxide (ZnO). The percentage of transmittance by TiO2/ZnO nanostructured thin films continue to improve as the calcination temperature were increased.

Potassium Bromide as Space Holder for Titanium Foam Preparation

Titanium (Ti) alloy foam was prepared by using potassium bromide (KBr) as space holder with percentage between 20 to 40 wt.%. In this work, the potential of KBr as a new space holder was determined. The Ti alloy powder and space holder were first manually mixed before being compacted using hydraulic hand press. The green compacts were then sintered at temperature of 1160°C, 1200°C and 1240°C in a tube furnace. The microstructure of the Ti alloy foams were observed by Scanning Electron Microscope (SEM). It was revealed that the porosity content in the Ti foam was in the range of 16% to 31% and density in the range of 1.5 g/cm3 to 2.6 g/cm3. Moreover, the pore size of the titanium alloy foam is in the range of 187μm to 303μm. Although the sintering temperatures were found incapable of promoting overall densification to the Ti alloy foam, 1200°C was denoted to be the maximal temperature for promoting maximal porosity to the Ti alloy foam. Nonetheless, KBr was proven to be suitable as space holder for Ti foam preparation as referred to its stability and insolubility in the Ti alloy.

Growth of ZnO Thin Films on Silicon Substrates by Atomic Layer Deposition

Atomic Layer Deposition (ALD) Offers the Key Benefits of Precise Deposition of Nanostructured Thin Films with Excellent Conformal Coverage. ALD Is Being Used in the Semiconductor Industry for Producing High-k (high Permittivity) Gate Oxides and High-K Memory Capacitor Dielectrics. Zno Has Attractive Properties for Various Applications such as Semiconductors, Gas Sensors and Solar Cells. in this Study, ZnO Thin Films Were Deposited via ALD Using Alternating Exposures of Diethyl Zinc (DEZ) and Deionized Water (H2O) on Silicon Wafer (100). the Thin Films Were Analyzed Using X-Ray Diffraction (XRD), Ellipsometer and Atomic Force Microscope (AFM). the XRD Analysis Shows the Presence of ZnO Thin Films with a Hexagonal Wurtzite Structure. the Thickness of ZnO Thin Films Was Correlated with the Substrate Temperatures and Deposition Cycles. the Coating Thickness Was Found to Increase with the Increase of the Deposition Cycles, but it Decreased with the Increase of Deposition Temperature. the Nucleation and Growth Mechanism of Zno Thin Film Has Been Established. it Can Be Concluded that, the Growth Mechanism of Zno Films Is Strongly Dependent on the ALD Processing Conditions.

Structural and Optical Characterization of TiO2/ZnO Thin Films Prepared by Sol-Gel Method

Thin film has been extensively study due to better structural, surface morphology, and optical properties. The combination of two materials will enhance the properties of thin film. In this study, TiO2/ZnO thin films were deposited on glass substrates via sol-gel method. TiO2 acts as pre-deposited thin film with calcination temperatures at 400 °C, 500 °C, and 600 °C. The post-deposition of TiO2/ZnO thin films were calcined at 500 °C and 600 °C. TiO2 sol-gel was synthesis from titanium (IV) butoxide and butanol as the precursor, while ZnO sol-gel was synthesis from zinc acetate dehydrate and isopropanol as the precursor. The TiO2/ZnO thin films were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), and ultraviolet visible spectroscopy (UV-Vis). The effect of calcination temperature and pre-deposited TiO2 thin films show difference results of bilayer thin films. The XRD analysis shows all TiO2/ZnO thin films growth with TiO2 anatase crystalline phase at orientation (1 0 1) and ZnO zincite phase at orientation (1 0 1). The structural properties of TiO2/ZnO thin films were improved by controlling the calcination temperature. Based on AFM analysis, the RMS value for TiO2/ZnO decreases as the calcination temperature increased. The compacted and dense surface roughness were controlled by the temperature. Meanwhile, the percentage of thin film ultraviolet transmittance can be enhanced with combination of two materials, TiO2 and ZnO. Therefore, the pre-deposited layer of thin film with influenced by calcination temperature will improve the crystallinity, surface morphology, and optical properties of TiO2/ZnO thin films.

Effects of Soda Lime Silicate Content on Industrial Stoneware Bodies Prepared by Pressing Method

Stoneware clay includes ball clay in every respect except that do not sintering to a white product. Indeed, stoneware containing soda lime silicate could improve physical and mechanical properties. Thus, the aim of this study was to investigate influence of soda lime silicate content on industrial stoneware bodies with different weight percent (wt%) at sintering temperature 950 °C and 1100 °C. Rectangular sample were produced by uniaxial pressing at 40 MPa. Chemical composition was determined by using XRF. The thermal behavior was determined by thermogravimetric and different thermal analysis (TGA-DTA). The scanning electron microscopy (SEM) was used for microstructure analysis. The water absorption of the sample was determined using Archimedes’ method. The mechanical strength of stoneware bodies is important for many type applications and can be determined by measuring flexural strength (MOR). The water absorption decreased with optimum weight percent (wt%) of soda lime silicate into industrial stoneware bodies. The experimental result showed that desirable properties of stoneware bodies can be achieved with 5 wt% of soda lime silicate. As conclusion, optimum 5 wt% of soda lime silicate will influence physical and mechanical properties of industrial stoneware bodies.

Synthesis of carbon nanostructures from high density polyethylene (HDPE) and polyethylene terephthalate (PET) waste by chemical vapour deposition

In this study, carbon nanostructures were synthesized from High Density Polyethylene (HDPE) and Polyethylene terephthalate (PET) waste by single-stage chemical vapour deposition (CVD) method. In CVD, iron was used as catalyst and pyrolitic of carbon source was conducted at temperature 700, 800 and 900oC for 30 minutes. Argon gas was used as carrier gas with flow at 90 sccm. The synthesized carbon nanostructures were characterized by FESEM, EDS and calculation of carbon yield (%). FESEM micrograph shows that the carbon nanostructures were only grown as nanofilament when synthesized from PET waste. The synthesization of carbon nanostructure at 700oC was produced smooth and the smallest diameter nanofilament compared to others. The carbon yield of synthesized carbon nanostructures from PET was lower from HDPE. Furthermore, the carbon yield is recorded to increase with increasing of reaction temperature for all samples. Elemental study by EDS analysis were carried out and the formation of carbon nanostructures was confirmed after CVD process. Utilization of polymer waste to produce carbon nanostructures is beneficial to ensure that the carbon nanotechnology will be sustained in future.

Influent of Borax Decahydrate Composition as Additional Flux into Stoneware Bodies

Stoneware is vitrified, has less porosity and requires high sintering temperature. The influent of borax decahydrate composition at sintering temperature 1050°C and 1150°C on the thermal analysis, fracture surface, linear shrinkage, water absorption and modular of rapture (MOR) were investigated. Rectangular sample were produced by uniaxially pressing at 40MPa. The thermal behavior was determined by thermogravimetric and different thermal analysis (TGA-DTA). The Scanning electron microscopy (SEM) was used for fracture surface analysis. The water absorption (%) of the sample were determined using Archimedes’ method. The experimental result showed that content of borax decahydrate have influent the properties of stoneware bodies.

Nanostructure of aluminium (Al) – Doped zinc oxide (AZO) thin films

Aluminium (Al)-doped Zinc Oxide (ZnO) was deposited on glass substrates by using the sol-gel dip coating technique. Next, AZO sol-gel solution was produced via sol-gel method. Al was used as doped element with molar ratios of 1%, 2%, and 3%, while the calcination temperatures were set at 400°C, 500°C, and 600°C for 2 hours. In fact, characterization was carried out in order to determine the effect of calcination temperature and molar ratio of doping by using several techniques, such as X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FESEM), and Ultraviolet-Visible spectroscopy (UV–Vis). XRD was performed to investigate the crystal structure in which the ZnO was in wurtzite hexagonal form. Next, Energy Dispersive Spectroscopy (EDS) was used to determine the composition of thin films where the result revealed the existence of zinc, oxygen, and aluminium. The roughness of the deposited film was later measured by using the AFM approach where the findings in...

The Effect of Substrate on TiO 2 Thin Films Deposited by Atomic Layer Deposition (ALD)

ALD is a precision growth technique that can deposit either amorphous or polycrystalline thin films on a variety of substrates. The difference in substrate can cause a variation in the ALD process, even it is carried out using the same reactants and deposition conditions [1]. TiO2 thin films were grown using TTIP (Titanium isopropoxide) ALD on silicon wafers, glass slides, and stainless steel plates in order to study the effect of substrates on the growth of TiO2 with 3,000 deposition cycles, at 300°C.The thin films were analyzed using Xray Diffraction (XRD), Raman Spectroscopy, Atomic Force Microscope (AFM) and Spectroscopic Ellipsometer. From XRD analysis were indicates the main peak for anatase (101) (2θ= 25.3) was observed from the XRD patterns for TiO2 on all substrates. The results show that crystalline TiO2 thin films can easily grow on a crystal substrate rather than on an amorphous substrate.