A Catalyst-Free Growth of ZnO Nanowires on Si (100) Substrates: Effect of Substrate Position on Morphological, Structural and Optical Properties (original) (raw)
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Korean Journal of Chemical Engineering, 2006
Synthesis of ZnO nanowires was achieved on Si(100) substrate by the thermal evaporation of high purity metallic zinc powder without the use of any metal catalyst or additives. The diameter and length of the as-grown nanowires were in the range of 20–35 nm and few micrometers, respectively. The shapes and sizes of ZnO nanowires were dependent on the growth time. The high resolution transmission electron microscopy and selected area electron diffraction patterns indicated that the as-grown products are single crystalline with wurtzite hexagonal phase. Room temperature photoluminescence studies exhibited a strong UV emission and a suppressed green emission, confirming the good optical properties for the deposited nanowires.
Non-catalytic growth of high aspect-ratio ZnO nanowires by thermal evaporation
Solid State Communications, 2006
High-density and high aspect-ratio ZnO nanowires were grown on Si(100) substrates by the thermal evaporation of metallic zinc powder without the use of metal catalysts or additives. The as-grown nanowires had diameters in the range of 60-100 nm with lengths 5-15 µm. Detailed structural characterization indicated that the obtained nanowires are single-crystalline with a perfect hexagonal facet and surfaces. The room temperature PL spectrum exhibited strong UV emission, affirming that the as-grown products have good optical properties. The possible growth mechanism for the formation of hexagonal-faceted and perfect surface ZnO nanowires is also discussed.
Journal of Alloys and Compounds, 2009
ZnO nanowires were grown on Si(1 0 0) and Si(1 1 1) substrates by a simple physical deposition method in a conventional tube furnace without the use of any catalyst. The substrates were placed at different temperature zones. ZnO nanowires with different diameters were obtained at different substrate temperatures. Photoluminescence (PL) spectroscopy has been employed to study the optical properties of ZnO nanowires with average diameters ranging from 29 to 75 nm. The shapes of the photoluminescence curves are dependent on the temperature and orientation of substrates. The ultraviolet photoluminescence peak exhibited a blue-shift in position with a decrease in the diameter of nanowires. Large diameter nanowires tend to have more intense UV emission.
Photoluminescence properties of ZnO nanowire arrays fabricated on silicon substrate
2013 13th IEEE International Conference on Nanotechnology (IEEE-NANO 2013), 2013
Photoluminescence studies of zinc oxide nanowires produced by a carbo--thermal method on a nickel foil substrate are reported. Two types of as--grown samples: the first -containing only buffer film, and the secondcontaining both zinc oxide nanowires and buffer film grown in the same technological process, were investigated by means of the temperature-dependent photoluminescence. X-ray diffraction measurements of buffer film show that it is polycrystalline and is composed from wurtzite-type ZnO (main phase) and includes minority phases: rock salt type (Ni,Zn)O and hexagonal C3N4. The shape of the apparently monocrystalline nanowires is characterized by hexagonal section matching with the expectations of the hexagonal ZnO structure. The presence of LO-phonon replicas in photoluminescence spectra for the second sample is used as an argument for confirmation that ZnO nanowires are single crystalline. The method of growth of ZnO nanowires on nickel oxide opens perspectives to produce Zn1−xNixO diluted magnetic semiconductor nanowires.
Effects of Deposition Parameters of Hydrothermal Method on Synthesis of ZnO-based Nanowires
Sensors and Materials, 2019
(NO 3) 2 ‧6H 2 O, ZnO-based nanowires, growth time ZnO-based nanomaterials can be used as sensors for different applications, including gas and ultraviolet (UV) ray sensors. To grow ZnO nanowires by the hydrothermal method, a ZnO seed layer was prepared by a sputtering method to deposit ZnO films on SiO 2 /Si substrates of about 200 nm thickness. Next, Zn(NO 3) 2 ‧6H 2 O and C 6 H 12 N 4 were used as reagents, and DI water was used as a solvent, and they were mixed to the designed compositions. We found that when Zn(NO 3) 2 ‧6H 2 O and C 6 H 12 N 4 were used as reagents to grow ZnO nanostructured materials, growth temperature, the concentration of the diluted solution, growth time, and the position of the substrates were four important factors affecting the synthesis results. The surface morphologies of ZnO nanowires were observed by field-emission scanning electron microscopy (FESEM), and crystalline phases were analyzed using X-ray diffraction (XRD) patterns. The FESEM images and XRD patterns were used to determine the effects of synthesis parameters on the morphologies and crystalline properties of the grown nanostructured materials. First, we found that 100 ℃ was the optimum synthesis temperature for growing pure ZnO nanowires, because ZnO-based nanowires could be successfully synthesized at different concentrations of Zn(NO 3) 2 ‧6H 2 O and C 6 H 12 N 4 and different synthesis times. The effects of growth time, the position of the substrates on the carry sheet glass, and concentrations of Zn(NO 3) 2 ‧6H 2 O and C 6 H 12 N 4 on the growth of nanostructured materials were also investigated.
Effect of growth temperature on the ZnO nanowires prepared by thermal heating of Zn powders
Current Applied …, 2010
ZnO nanowires have been synthesized by heating Zn powders under nitrogen (N 2 ) gas atmosphere. The influence of the growth temperature on the morphology, structure, and photoluminescence (PL) properties of ZnO nanowires has been investigated. At the higher-temperature growth process, thinner nanowires have been obtained. Interestingly, it is observed that the variation of growth temperature has significantly affected the photoluminescence spectra of the ZnO nanowires, showing an enhancement in the relative intensity of the green to UV emission bands with the increase of the growth temperature. In addition, the oxygen sensing properties of the as-synthesized ZnO nanowires were tested.
Study of the Substrate Influence in ZnO Nanowires Oriented Growth
Procedia Materials Science, 2015
A solution growth approach for zinc oxide (ZnO) nanowires is highly appealing because of the low growth temperature and possibility for large area synthesis. In our work, ZnO nanowires were obtained from thin films prepared on silica glass, Si (100) and Si (111) from a single and five layers spin-coating deposition of a sol-gel prepared with dehydrate zinc acetate, monoethanolamine and isopropanol. Crystallization annealing was performed at 450 °C. These films were used as seed layer to prepare ZnO nanowires/nanorods from a zinc nitrate and hexamethylenetetramine solution. X-ray diffraction analysis showed that nanowires/nanorods grown on Si (111) were preferentially orientated along the [002] direction.
High-quality ZnO nanowire arrays directly synthesized from Zn vapor deposition without catalyst
Journal of the Korean Crystal Growth and Crystal Technology
Vertically well-aligned ZnO nanowire (NW) arrays were synthesized directly on GaN/sapphire and Si substrate from Zn vapor deposition without catalysts. Experimental results showed that the number density, diameter, crystallinity and degree of the alignment of ZnO NWs depended strongly on both the substrate position and kind of the substrates used for the growth. The photoluminescence (PL) characteristics of the grown ZnO NW arrays exhibit a strong and sharp ultraviolet (UV) emission at 379 nm and a broad weak emission in the visible range, indicating that the obtained ZnO NWs have a high crystal quality with excellent optical properties. The as-grown ZnO NWs were characterized by using scanning electron microscopy (SEM), high resolution transmission electronic microscopy (HR-TEM), and X-ray diffraction (XRD).
Growth and characterization of ZnO nanowires for optical applications
Laser Physics, 2013
In the present work, cerium oxide CeO 2 nanoparticles were synthesized by the sol-gel method and used for the growth of ZnO nanorods. The synthesized nanoparticles were studied by x-ray diffraction (XRD) and Raman spectroscopic techniques. Furthermore, these nanoparticles were used as the seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by means of field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and XRD techniques. This study demonstrated that the grown ZnO nanorods are well aligned, uniform, of good crystal quality and have diameters of less than 200 nm. Energy dispersive x-ray (EDX) analysis revealed that the ZnO nanorods are composed only of zinc, cerium as the seed atom, and oxygen atoms, with no other impurities in the grown nanorods. Moreover, a photoluminescence (PL) approach was applied for the optical characterization, and it was observed that the near-band-edge (NBE) emission was the same as that of the zinc acetate seed layer, however the green and orange/red emission peaks were slightly raised due to possibly higher levels of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the controlled synthesis of ZnO nanorods using cerium oxide nanoparticles as the seed nucleation layer, improving both the morphology of the nanorods and the performance of devices based upon them.
We report on the growth of ZnO nanostructures on n-type silicon substrate using pulsed laser deposition technique at substrate temperature ranging from room temperature to 600 ∘ C for one hour. We observe both rod-and wire-like structures with different dimensions at room temperature, 150 ∘ C, and 450 ∘ C substrate temperatures and only wire-like structures at 300 ∘ C and 600 ∘ C. These combinations of different shapes have been attributed to the initial growth of nanostructures (nucleation sites) on the surface obtained during the deposition for 20 minutes. The narrowing in the full-width-half-maximum of the peak corresponding to (002) plane of XRD is looked upon as another possible explanation. The blue shift of the peak at 396 nm observed in the photoluminescence is due to the quantum confinement. The intensity of 2 (high) mode at 437 cm −1 increases indicating improvement in crystallinity with the substrate temperature.