Che Ani Norhidayah

Influence of Gd Doping on the Structural and Optical Properties of ZnO

Doping transition metal or rare-earth metal ion are one of the most popular topics in semiconductors. In this work, gadolinium (Gd) doped zinc oxide thin films was prepared using spin-coating technique with different concentrations in atomic percent (at.%). The influences of rare-earth ions doped into the zinc oxide films were studies. The effects on the physical and optical properties of the films were investigated by field emission scanning electron microscope, x-ray diffraction, atomic force microscopic and ultraviolet-visible spectrophotometer. It was found that the properties of zinc oxide can be tuned by changing the concentration physical and optical of Gd.

Physical and optical studies on ZnO films by SOL-GEL

Zinc oxide (ZnO) is a new material used in electronics applications such as spintronics, diluted magnetic semiconductor (DMS) and thin films. In this paper, the findings in fabrication and characterization of ZnO nanoparticles are reported. ZnO thin films were deposited onto glass substrates using a spin coating techniques at different pre-annealing temperatures. The optical transmittance measurement of the ZnO nanostructures was examined using an ultraviolet-visible spectrophotometer (UV-Vis) with wavelength ranging from 300-800 nm. On the other hand, the topography and film roughness were, measured by an atomic force microscope (AFM). The surface morphologies was obtained using a field emission scanning electron microscope (FESEM) and showed that the ZnO nanoparticles are distributed uniformly.

Synthesis and Characterization of Zinc Oxide Nanostructures by Different Sonication Period

Zinc oxide (ZnO) is a wide band gap semiconductor material (3.37 eV) with numerous present applications such as varistors, surface acoustic wave devices and future biomedical applications. ZnO nanorods were grown under specific growth condition by an inexpensive and simple, chemical bath deposition method on ZnO seeded glass substrates. Study of the ZnO nanorods over different precursors, i.e zinc acetate dehydrate and zinc nitrate hexahydrate, and sonication period ranging from 0 to 120 seconds by field emission scanning electron microscope (FESEM), including the nanorod size and the surface morphology, will be demonstrated in this paper. Characterization of the ZnO film using both X-ray diffraction (XRD) and UV-Vis spectroscopy will be established in determining the optimal composition along with the optical properties, respectively.

Effects of Ageing Time of ZnO Sol on Properties of ZnO Films by Sol Gel Spin Coating

In recent years, there are many techniques developed to synthesize zinc oxide (ZnO) films. However, among the synthesis methods available, sol-gel has the most advantageous which offers cost effective features. In the present work, ZnO films were prepared by solgel spin coating technique. The effects of solution ageing times which varies at 2h 15 min, 3h 30 min and 24h were investigated. The structural, morphological and optical properties were studied using an x-ray diffractometer (XRD, Bruker D8 Advance), atomic force microscope (AFM, Tenko XE-100) and ultra violet-visible spectrophotometer (UV-Vis, Shimadzu UV 1800), respectively. Based on the XRD measurement, it was revealed that ZnO films were polycrystalline with hexagonal wurtzite structure. The crystallite size is in the range of 34.4 ~ 28 nm which decreased with ageing time increment. On the other hand, the AFM analysis revealed that the surface roughness of the films increased due to the increment of ageing times. Optical transmittance spectra indicate that all films were transparent (>75%) in the visible range which slightly improved with increasing of ageing times. The optical band gap was estimated to be around 3.24 ~3.26 eV using Taucs plot. We revealed that the ageing time of ZnO sol influenced the material properties of ZnO films. Based on our finding we proposed that 24h ageing time is optimum for the fabrication of high quality ZnO films.

Derivation of GdxZn1-xO Film: The Effects of Gd Concentration on the Structural, Morphological and Optical Properties

In recent years there has been renewed interest in zinc oxide semiconductor, mainly triggered by its prospects in optoelectronic applications. Doping ZnO with various elements has been a popular technique to gain the extrinsic properties for device applications. In this work we have studied the effect of Gadolinium (Gd) concentration on properties of sol–gel derived Gd doped ZnO films. The Gd concentration varying from 1 to 8 atomic percent (at.%). The structural, morphological and optical analyses were monitored by (XRD, Bruker D8 Advance), atomic force microscope (AFM, Tenko XE-100) and ultra violet-visible spectrophotometer (UV-Vis, Shimadzu UV 1800), respectively. Observations from the XRD results showed that all films exhibit the hexagonal wurtzite crystal structure and higher peak intensity observed at (002) peak. Based on XRD analysis, we also found that Gd concentration has a significant effect on the crystallite size and strain of the films. Moreover, the AFM analysis revealed that the surface become more uniform and denser as the Gd concentration increased. In addition, the optical transmittance spectra indicate that all films were highly transparent (>90%) in the visible range which slightly improved with increasing Gd concentration. The detail explanation on the mechanism will be discussed in detail in this paper.

2D and 3D Analyses of Metal Oxide Thin Films Examined by Atomic Force Microscope

Atomic force microscope (AFM) is a useful tool to capture the two- and three-dimensional image of height and size of nanostructured thin film. It operate by measuring the forces between a sharp tip and surface of the measured sample. In addition, AFM is equipped with powerful software for image processing to interpret experimental results in detail. For example, by using the height and scanning length parameters of measured sample, average roughness and root mean square roughness can be evaluated. In the present works, the effect of image flattening process toward the surface roughness and surface fluctuations of metal oxide thin films will be presented. Set of samples were prepared by magnetron sputtering deposition and sol-gel coating techniques. In gas sensor industries using metal oxide thin film, surface roughness of metal oxide thin films are very important in order to improve the sensitivity and respond time of gas sensor. Therefore, optimization of thin film deposition and characterization are very important. The correlation between the three-dimensional image and thin film deposition and image processing parameters will also be presented.

A Study on the role of solvent on properties of Gd x Zn 1−x O films synthesized by sol-gel method

The increasing demand for high-performance and low cost optoelectronic devices motivates many researchers to develop more efficient transparent conductive oxide (TCO) films. Among the popular TCOs, the past decade has seen the emergence of zinc oxide (ZnO) as one of the potential materials for the fabrication of transparent conductive electrodes. The aim of this work is to study the influence of different solvents on the properties of GdxZn1-xO (x ≤ 0.01) films synthesized by sol-gel spin coating technique. Consequently, three different solutions were prepared with different solvents [2-Methoxyethanol (2-ME), ethanol (EtOH) and isopropanol (IPA)]. The structural, surface roughness and optical properties were investigated using an X-ray diffractometer (XRD, PANanalytical xpert-pro), atomic force microscope (AFM, Park XE-100) and ultra violet-visible spectrophotometer (UV-Vis, Shimadzu UV 1800), respectively. As a result, all films were found to have polycrystalline with hexagonal wurtzite structure. In addition, AFM analysis revealed that the film synthesized using EtOH exhibiting the smallest surface roughness of about 4.12 nm compared with IPA and 2-ME of about 5.12 nm and 12.22 nm, respectively. Also, the optical transmittance spectra indicate that all films exhibit good transparency in the visible spectral range with an average transmission of approximately 97.5%, 97.2% and 96.1% for EtOH, IPA and 2-ME, respectively. The optical band gap energy (Eg) values was estimated to be around 3.26 ~ 3.30 eV using Taucs model with the lowest value for IPA (3.26 eV) and highest for 2-ME (3.30 eV). In a nutshell, the solvents are playing a key role for controlling the growth and nucleation in the preparation of GdxZn1-xO solution and it strongly affects the properties of the film.

Performance of P3HT:PCBM Organic Solar Cell with ZnO Buffer Layer

In this paper, we explore the characteristics of bulk heterojunction solar cell based on poly (3-hexyl thiophene) [P3HT] and [6,6]-phenyl-C61-butyric acid methyl ester [PCBM] by introducing a buffer layer with device configuration of ITO/ZnO/P3HT:PCBM/Au. Nanostructured ZnO with individual diameter around 20-50 nm was used as the buffer layer and its effects on the short circuit current density, Jsc and open circuit voltage, Voc were investigated. It was found that, the electrical characteristic of the organic solar cell was obviously changed by introducing the buffer layer. Solar cell characteristic with Voc of 0.3939 V was obtained but the Jsc was very small. The surface topology of the P3HT:PCBM was investigated using an atomic force microscopy (AFM). ZnO nanoparticles were observed using a field emission scanning electron microscope (FESEM) and the electrical properties of the solar cell was measured using a solar simulator with a current – voltage (I-V) measurement system.