The influence of Sn doping on the structural and morphology of ZnO nanowire deposited using PVD technique (original) (raw)
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Effects of Sn doping on the growth morphology and electrical properties of ZnO nanowires
Nanotechnology, 2013
This study examines the effects of doping ZnO nanowires (NWs) with Sn on the growth morphology and electrical properties. ZnO NWs with various Sn contents (1-3 at.%) were synthesized using the vapor-liquid-solid method. Scanning electron and transmission electron microscopy analyses showed that all of the Sn-doped NWs grew in a bamboo-like morphology, in which stacking faults enriched with Sn were periodically inserted. We fabricated a hybrid film of InZnO sol-gel and Sn-doped ZnO NW networks to characterize the effects of Sn doping on the electrical properties of the NWs. With increasing doping density, the carrier concentration increases significantly while the mobility decreases greatly. The resistivity remains scattered, which suggests that Sn doping in ZnO is not an effective method for the enhancement of conductivity, since Sn does not readily incorporate into the ZnO structure.
Scanning probe microscopy of ZnO nanobelts
2009
We present an AFM and STM-STS investigation of the surface of ZnO nanobelts grown by chemical vapour deposition. AFM images showed a type 1 (high aspect ratio) nanobelt lying across a type 2 (low aspect ratio) nanobelt, bending at an angle of 20.9 • without breaking. Terraces 10 atomic layer thick were also observed, with step edges running along the [0010] direction. STM images confirmed the AFM results while STS curves and current maps showed higher conductivity for the ZnO nanobelts than for the oxidised silicon surface, as well as an n-type behaviour.
Comparative study on the properties of ZnO nanowires and nanocrystalline thin films
Surface and Coatings Technology, 2012
The microstructural, morphological, optical and water-adsorption properties of nanocrystalline ZnO thin films and ZnO nanowires were studied and compared. The ZnO thin films were obtained by a sol-gel process, while the ZnO nanowires were electrochemically grown onto a ZnO sol-gel spin-coated seed layer. Thin films and nanowires samples were deposited onto crystalline quartz substrates covered by an Au electrode, able to be used in a quartz crystal microbalance. X-ray diffraction measurements reveal in both cases a typical diffraction pattern of ZnO wurtzite structure. Scanning electron microscopic images of nanowires samples show the presence of nanowires with hexagonal sections, with diameters ranging from 30 to 90 nm. Optical characterization reveals a bandgap energy of 3.29 eV for the nanowires and 3.35 eV for the thin films. A quartz crystal microbalance placed in a vacuum chamber was used to quantify the amount and kinetics of water adsorption onto the samples. Nanowire samples, which have higher surface areas than the thin films, adsorb significantly more water.
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.
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.
Nanotechnology, 2006
ZnO nanowires and nanobelts are two representatives of one-dimensional semiconductor nanomaterials possessing potential applications as optoelectronic and sensor devices. In this study, we applied a vapour-transport-deposition method to synthesize both types of nanostructures using relatively low temperatures (860 • C) by controlling the source materials. We found that the resulting product under similar growth conditions can be switched between [0001]-axial nanowires and 1120-axial nanobelts simply by adding indium to the source. The former appear as ordered vertical arrays of pure ZnO while the latter are belts without spatial ordering. Both represent defect-free single crystals grown via the vapour-liquid-solid mechanism using nanosphere lithography-fabricated catalyst Au templates. Examination of the early growth stage suggests that the dissolution of In into Au influences the nucleation of ZnO at the solid-liquid interface, and subsequently defines the structure and crystallographic orientation of the nanobelts. The optical properties of both nanostructures are studied by photoluminescence and resonant Raman scattering, which indicate consistently that the doped nanobelts have a higher carrier concentration than the nanowires.
Direct Synthesis of ZnO Nanowires on Nanopatterned Surface by Magnetron Sputtering
Chemical Vapor Deposition, 2011
ZnO nanowire arrays parallel to the substrate are directly deposited by magnetron sputtering on the top of nanometric silicon line patterns prepared as a template. This method of synthesis is very simple and avoids the complicated steps of ZnO lithography. The nanoline template patterns are created by laser interference lithography combined with deep reactive ion etching. The assembly and the alignment of the nanowires after the deposition process are studied by scanning electron microscopy (SEM). The dimensions of the nanowires are regulated by those of the nanoline template patterns. The nanowires of 150 nm in width, 90 nm in height, 20 mm in length are fabricated especially for the study of their microstructure and photoluminescence effects. The microstructure is explored by X-ray diffraction (XRD) and high-resolution (HR) transmission electron microscopy (TEM). The nanowires show well-crystallized ZnO nanograins in the hexagonal wü rtzite structure with a (002) preferential orientation on the (100) silicon surface. The nanowires exhibit a typical photoluminescence spectrum of ZnO.
Synthesis and Characterization of Zinc Oxide (ZnO) Nanowire
Journal of Nanomedicine & Nanotechnology, 2015
Nanowires are structures that have a lateral size constraint to tens of nanometers or less and an unconstrained longitudinal size. The syntheses and characterization of ZnO nanowire with hexagonal structure was successfully achieved using chemical bath deposition technique. The nanowires obtained were further characterized by scan electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX) and spectrophotometer. The SEM micrographs revealed the morphology of ZnO nanowires with diameter 170.3 nm and 481 nm. This revealed that the pH 8.1 of the bath solution and the optimized value form ZnO nanowires with hexagonal shape at top surface. The XRD pattern of the samples revealed ZnO nanowire have hexagonal crystallite structure. Where upon the crystallite size supported increased annealing temperature (0.536 nm, 0.541 nm and 0.557 nm at 100°C, 150°C and 200°C respectively). The EDX analysis revealed the elemental compositions of samples and confirmed the presence of Zn and O2. The results of the optical analysis showed that ZnO nanowire have high absorbance in the ultraviolet and infrared regions with high transmittance in the visible region. The absorbance of the nanowire increases with increasing annealing temperature. Its high absorbance in the ultraviolet region suggest it applicability as solar harvester for trapping solar energy, used for photovoltaic panel with capacity to converting sunlight radiation directly to electricity for commercial or industrial purposes.
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.
Nanoscale Research Letters, 2012
In this study, we synthesized various dimensionalities of ZnO nanowires using the Ti grid-assisted chemical vapor deposition process. Energy dispersive X-ray spectroscopic mapping technique accompanied with a lattice diffusion model was used to characterize the growth mechanism. A diffusion ratio γ, defined by short-circuit and lattice diffusion activation energies, was obtained to describe the growth mechanism of ZnO nanowires. The tunable dimensionalities of ZnO nanowires allow us to modify the morphology of ZnO nanocrystals by developing well-controlled potential applications.