Investigation of Optical Properties of ZnO Nanorods Grown on Different Substrates (original) (raw)
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Journal of Electronic Materials, 2021
Zinc oxide (ZnO) nanorods (NRs) have been investigated as a function of different growth temperature using modified chemical bath deposition (M-CBD) method. In this study, air bubbles were utilized inside the growth solution as an original modified process. The synthesis of ZnO NRs was carried out through two steps. The first step was deposition of the ZnO seed layer on the glass substrate, while the second step was growing the ZnO NRs on the seeded substrate. The impacts of the growth temperature on the morphology and crystal structure of the ZnO samples were investigated using field emission scanning electron microscopy and x-ray diffraction. UV-Vis spectroscopy was also utilized to characterize the optical properties of the ZnO NRs. The results showed that the growth of the ZnO samples is a NRs-like shape. The ZnO samples possess the hexagonal wurtzite structure with high crystal quality, and no other phases from the impurity were observed. Additionally,the ZnO NRs were found to be well oriented along te (002) planes with diameters ranging from 71 nm to 328 nm and length from 294 nm to 2475 nm, while the aspect ratio was up to 25 with different growth temperatures. However, the UV-Vis spectrum showed that the optical transmittance of the ZnO NRs dropped from $ 66% to $ 3.3%, and the absorption band edge had been shifted to a lower-energy region as the growth temperature increased from 65°C to 95°C. This is possibly due to the scattering increase and absorption light from voids, grain size, and thickness of the ZnO NRs. Therefore, it has been demonstrated that the ZnO NRs grown by the M-CBD method at a growth temperature of 95°C gives the most favorable result, since the NRs possess the optimum, homogenous, and uniform distribution with a higher aspect ratio, crystal quality, crystal size, and band gap energy.
Lecture Notes in Mechanical Engineering, 2021
Comparative analysis on morphological, structural, and optical between zinc oxide (ZnO) nanorods on unseeded and seeded glass substrates was estimated. Both samples were synthesized by simple solution immersion method and annealed at 500°C for 1 h. The morphological, structural, and optical properties of the investigated ZnO nanorods were characterized using Field Emission Scanning Electron Microscopy (FESEM), X-Ray diffraction (XRD) spectroscopy, and Ultraviolet-Visible Spectroscopy (UV-vis), respectively. Average diameter size of ZnO on seeded glass substrates calculated from FESEM was 90 nm, four-fold smaller from the sample on the non-seeded layer. The wurtzite ZnO showed rod arrays morphology. It was found out that the (002) peak is the most dominant, indicating that the ZnO grows preferentially along the c-axis. No other peaks are suggesting that no impurities other than pure ZnO were obtained. The optical band gaps of seeded glass substrates ZnO nanorods decreased to 3.48 eV. High crystalline of ZnO nanorods on seeded glass substrate was achieved and can be beneficial for optoelectronics application.
The Effect of Growth Temperature on The Characteristics Of ZnO Nanorods And Its Optical Properties
Journal of physics, 2018
The aim of this research is to identify the effects of growth temperature on the characteristics of ZnO nanorods synthesized by the hydrothermal method. The Zinc oxide (ZnO) nanorods synthesis was carried out through two steps, consisting of the ZnO seed layer deposition and the ZnO nanorods growth. The ZnO seed layer was prepared by a spin coating method using zinc acetate dehydrate and ethanol on ITO substrate. The following ZnO nanorods growth was performed with the modified hydrothermal method by using hexamethylenetetramine (HMT) as a precursor and zinc nitrate with a molar ratio of 1:1 for 6 hours. A variation of ZnO nanorods growth temperatures of HMT 25 mM and 50 mM was performed in this research. The resulted ZnO nanorods were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to study their structures and morphology. Transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-Vis) were utilized to characterize the optical characteristics of ZnO nanorods. In general, the synthesized ZnO nanorods were found to be oriented on the (100) and (101) planes with diameters ranging from 81 nm until 365 nm and rods lengths up to 5.1 m. The HMT 50 mM concentration showed that the higher the growth temperature, the larger the sizes of diameter and length of the ZnO nanorods. The ZnO nanorods synthesized by using the 50 mM HMT concentration at 80 oC presented the most favorable result since it had a small size, diameter, and crystallite size with a large energy gap.
IOP Conference Series: Materials Science and Engineering, 2019
Owing to their high surface to volume ratio and fast electron transfer, zinc oxide (ZnO) nanorods have been well-known as potential nanostructured material for various applications including sensors, dye sensitized solar cells, optoelectronic, transparent heater and biomedical devices. Among other synthesizing techniques for obtaining ZnO nanorods, chemical bath deposition (CBD) has been thought as a simple and low-cost method. However, there are several processing parameters that need to be investigated for the above-mentioned applications where the highly optical transparency of thin film ZnO nanorods grown on glass substrates is one of important targets to be achieved. In this work, ZnO nanorods were synthesized through CBD process at low temperature (0°C) by using seed solution prepared by dissolving 1: 1 equimolar zinc nitrate tetrahydrate and hexamethylene tetraamine. For investigation purposes, three different concentration of seed solutions i.e. 0.005, 0.025 and 0.05 M were ...
Pertanika Journal of Science and Technology
The effect of zinc oxide (ZnO) multilayer thin film thicknesses, deposited via the sol-gel spin coating technique, on the morphology, structural and optical properties of ZnO nanorods (ZNR) grown on the ZnO thin films were explored in this investigation. The ZNR was grown using the chemical bath deposition method on the ZnO thin film seed layer (SL). We found that ZnO thin film SL morphology changes according to the number of layers based on the results. Eventually, these changes also influence the structures of ZNR. ZNR structures improved when the thickness of the seed layer increased. Besides the surface roughness, better crystalline quality films were obtained when more layers were deposited. This crystalline quality then influenced the optical characteristics of both ZnO and ZNR thin films. The optical properties from UV-Vis showed transmittance in the visible region, showing that the ZnO films produced were suitable to be applied to solar cells. ZNR-based solar cells have beco...
Journal of Alloys and Compounds, 2011
We report on the synthesis of high-quality ZnO nanorods by combining hydrothermal growth (HG) and chemical vapor deposition (CVD) processes. Vertically aligned and closely packed ZnO nanorods were grown by HG on a sputtered ZnO seed layer on a SiO 2 /Si (0 0 1) substrate. The top surface of the HGprepared ZnO nanorods showed very flat surfaces compared with that of the sputtered ZnO seed layer. Therefore, the HG-prepared ZnO nanorods were used as a new alternative seed material for the CVD growth of the ZnO nanorods. Vertical ZnO nanorods were grown by CVD on both the new HG-prepared nanorod seed material and the sputtered ZnO seed layer. The CVD-prepared ZnO nanorods on new HGprepared nanorod seed material showed better crystalline quality and superior optical properties than the CVD-prepared ZnO nanorods on sputtered seed layer. The former showed negligible deep-level emissions at room temperature photoluminescence measurements. The intensity ratio of near-band-edge emissions to deep-level emissions from the former was about 910, but that from the latter was about 151. This implies that the HG-prepared ZnO nanorods can be used as a promising new seed material for nanostructure synthesis.
Growth Morphology and Optical Properties of ZnO Nanostructures on Different Substrates
Journal of Nanoscience and Nanotechnology, 2013
Growth of ZnO nano and microstructures were carried out by low temperature hydrothermal method on glass and silicon substrates without seed layer. Crystallographic orientation and morphology of the samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The transmittance measurements were done by Fourier transformed infrared (FTIR) spectroscopy and a Raman spectrometer was also deployed to understand the vibrational properties of ZnO nanocrystals. XRD and Raman studies showed the formation of hexagonal wurtzite phase of ZnO on both the substrates. Cactus and needle like nanostructures forming rosette superstructure were observed for ZnO on glass substrate. On Si(100), nanorods, tetrapods and multipodes were found with smaller crystallite size. More preferential growth and crystalline nature of ZnO on silicon substrate is discussed on the basis of lattice compatibility between ZnO and Si. The role of interface SiO 2 layer, the effective growth mechanism and properties of these nanostructures are also discussed.
Crystals
In this study, the effects of different precursor concentrations on the growth and characteristics properties of the zinc oxide (ZnO) nanorods (NRs) synthesized by using modified and conventional chemical bath deposition (CBD) methods were investigated. The morphologic, structural and optical properties of synthesized ZnO NRs with different precursor concentrations were studied using various characterization techniques. The experimental results show that the varying precursor concentration of the reactants has a remarkable and significant effect on the growth and characteristics properties of ZnO NRs. In addition, the characteristic properties of ZnO NRs grown using the modified method showed significantly improved and enhanced properties. The average length of grown ZnO NRs increased with increased precursor concentration; it can be seen that longer ZnO NRs have been investigated using the modified CBD methods. The ZnO NRs synthesized at 0.05 M using the modified method were grown ...
Formation of ZnO Nanostructures Grown on Si and SiO2 Substrates
ZnO nanorods are grown on Si-based substrate by chemical bath deposition method in aqueous solution using zinc nitrate hexahydrate. Various substrates having different surface morphology are used to evaluate their effect on growing ZnO nanorods, such as flat Si wafer, small and large textured-Si wafer, porous silicon, flat SiO 2 wafer, small and large textured-SiO 2 wafer. The length, diameter, geometry, and coverage density of ZnO nanorods are investigated by field-emission scanning electron microscopy and summarized. SiO 2 is a preferred substrate for the growth of ZnO nanorods to Si if the surface morphology of substrate is same, and the textured surface has much higher coverage density (> 95%) than the flat surface. Each nanorod is vertically grown along the c-axis on the top of each pyramid face for textured substrate, and forms the 3D sea sponge-like ZnO structure. The characteristics of ZnO nanorods grown on various substrates are analyzed by grazing-angle X-ray diffraction (XRD) and photoluminescence (PL) measurements.