Controllable Synthesis of ZnO Nanonails by Vapor-Solid Process: Growth Mechanism and Structural and Optical Properties

ABSTRACTSingle-crystalline with good optical properties aligned ZnO nanonails were grown on steel alloy substrate without the use of metal catalyst or additives by the thermal evaporation process using high purity metallic zinc powder and oxygen as source materials for zinc and oxygen, respectively. Detailed morphological studies by FESEM revealed that the obtained nanonails are grown in a high density over the whole substrate surface and are exhibiting perfect hexagonal-shaped caps. The diameters of the nanonails at their tops and bases are ranges from 120∼160nm and 50∼70 nm, respectively. The detailed structural characterizations confirmed that the synthesized nanostructures are single-crystalline and grown along the c-axis direction. Raman scattering and room-temperature photoluminescence studies demonstrated the wurtzite hexagonal phase and good optical properties, respectively for the grown nanonails.

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Low-Temperature Growth of Flower-Shaped UV-Emitting ZnO Nanostructures on Steel Alloy by Thermal Evaporation

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.857 ◽

2007 ◽

Vol 7 (12) ◽

pp. 4421-4427 ◽

Cited By ~ 4

Author(s):

Ahmad Umar ◽

S. H. Kim ◽

J. H. Kim ◽

Y. K. Park ◽

Y. B. Hahn

Keyword(s):

Thermal Evaporation ◽

Hexagonal Phase ◽

Zinc Powder ◽

Hexagonal Structure ◽

Structural Defects ◽

Metal Catalyst ◽

Steel Alloy ◽

Zno Nanostructures ◽

Uv Emission ◽

Wurtzite Hexagonal Phase

Flower-shaped ZnO nanostructures, containing the triangular-shaped petals (sharpened tips and wider bases) have been achieved by simple thermal evaporation of high purity metallic zinc powder in the presence of oxygen at 440 °C on steel alloy substrate without the use of metal catalyst or additives. Detailed structural studies confirm that the obtained flower-shaped nanostructures are single crystalline and possesses a wurtzite hexagonal structure, grown along the c-axis in the [0001] direction. Raman and room temperature photoluminescence analysis substantiate a wurtzite hexagonal phase with a good crystal quality and a strong UV emission at 378 nm, respectively, indicating few or no structural defects. Additionally, a detailed possible growth mechanism has also been discussed.

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Hierarchical ZnO Nanostructures: Growth and Optical Properties

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.18393 ◽

2008 ◽

Vol 8 (12) ◽

pp. 6355-6360

Author(s):

Ahmad Umar ◽

A. Al. Hajry ◽

S. Al-Heniti ◽

Y.-B. Hahn

Keyword(s):

Optical Properties ◽

Room Temperature ◽

Thermal Evaporation ◽

Hexagonal Phase ◽

Hierarchical Structures ◽

Zinc Powder ◽

Zno Nanostructures ◽

Hierarchical Nanostructures ◽

Uv Emission ◽

Wurtzite Hexagonal Phase

Growth of hierarchical ZnO nanostructures composed of ZnO nanoneedles have been achieved via simple thermal evaporation process by using metallic zinc powder in the presence of oxygen at low temperature of 460 °C on silicon substrate without the use of any kind of metal catalysts or additives. It is confirmed by detailed structural studies that the as-grown hierarchical nanostructures are single crystalline with a wurtzite hexagonal phase and nanoneedles of these structures are grown along the c-axis in the [0001] direction. The Raman-scattering analysis substantiates a wurtzite hexagonal phase with a good crystal quality for the as-grown products. Room-temperature photoluminescence (PL) exhibits a strong UV emission at 380 nm confirming the excellent optical properties of as-synthesized hierarchical structures. A plausible growth mechanism is also proposed to clearly understand the growth process of the synthesized structures.

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Two-Step Growth of Hexagonal-Shaped ZnO Nanowires and Nanorods and Their Properties

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.858 ◽

2007 ◽

Vol 7 (12) ◽

pp. 4522-4528 ◽

Cited By ~ 11

Author(s):

Ahmad Umar ◽

S. H. Kim ◽

J. H. Kim ◽

Y. B. Hahn

Keyword(s):

Hexagonal Phase ◽

Green Emission ◽

Zinc Powder ◽

Zno Nanowires ◽

Thermal Evaporation Method ◽

Single Crystalline ◽

Uv Emission ◽

Nano Structures ◽

Wurtzite Hexagonal Phase ◽

Step Growth

Single-crystalline with perfect hexagonal-shaped ZnO nanowires and nanorods, possessing the Zn-terminated (0001) facets bounded with the six-crystallographic equivalent {0110} surfaces, have been grown on Au-coated silicon substrate via thermal evaporation method using the metallic zinc powder in presence of oxygen. The detailed structural analyses reveal that the obtained nano-structures are single-crystalline with the wurtzite hexagonal phase and are preferentially oriented in the c-axis, [0001] direction. Raman spectra exhibit a sharp and strong optical phonon E2 mode at 437 cm−1 further confirms the good crystal quality with wurtzite hexagonal crystal structure for the deposited products. The room-temperature photoluminescence (PL) spectra, for both the structures, showed a sharp and strong UV emission with a suppressed green emission, indicating the good optical properties for the as-grown nanostructures.

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Hydroquinone Sensor Based on Neodymium (Nd) Doped ZnO Hexagonal Nanorods

Nanoscience and Nanotechnology Letters ◽

10.1166/nnl.2018.2620 ◽

2018 ◽

Vol 10 (3) ◽

pp. 351-357 ◽

Cited By ~ 1

Author(s):

Yas Al-Hadeethi ◽

Ahmad Umar ◽

Ahmed A. Ibrahim ◽

Rajesh Kumar ◽

Saleh. H. Al-Heniti ◽

...

Keyword(s):

Dynamic Range ◽

Hexagonal Phase ◽

Zno Nanorods ◽

High Sensitivity ◽

X Ray Diffraction ◽

Raman Scattering Spectroscopy ◽

Morphological Studies ◽

Wurtzite Hexagonal Phase ◽

Doped Zno ◽

Hexagonal Nanorods

Herein, we report a simple hydrothermal synthesis and detailed characterizations of Nd-doped ZnO pointed hexagonal nanorods by various techniques such as field emission scanning electron microscopy (FESEM) attached with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-visible, Fourier transform infrared (FTIR) and Raman-scattering spectroscopy. The morphological studies revealed pointed hexagonal nanorods arranged in flower-shaped morphologies and well-crystalline with the wurtzite hexagonal phase. The Nd-doped ZnO nanorods were used as potential scaffold to fabricate high sensitivity hydroquinone sensor which exhibited sensitivity of ∼7.43 μA·mM–1cm–2 with a linear dynamic range of (LDR) of 0.313 mM–2.5 mM and correlation coefficient (R2) of 0.99671. The detection limit of Nd-doped ZnO pointed hexagonal nanorods based hydroquinone sensor was found to be 0.313 mM.

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Structure and Optical Properties of SnS Nanowire Arrays Prepared with Two-Step Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.476-478.1519 ◽

2012 ◽

Vol 476-478 ◽

pp. 1519-1522 ◽

Cited By ~ 2

Author(s):

You Dao Lin ◽

Xin Wen ◽

Lai Sen Wang ◽

Guang Hui Yue ◽

Dong Liang Peng

Keyword(s):

Optical Properties ◽

Electrochemical Deposition ◽

Average Diameter ◽

Nanowire Arrays ◽

Step Method ◽

Single Crystalline ◽

Uv Visible

Abstract. Single crystalline SnS nanowire arrays have been synthesized by sulfurating the Sn nanowire arrays which were prepared with the electrochemical deposition. The obtained SnS nanowire arrays are charactered with the XRD, SEM, TEM and the UV/Visible/NIR spectrophotometer. And the results indicate that the nanowires with an average diameter of 50 nm and a length of several tens micrometers, which same with the as prepared Sn nanowires. There are two absorption peaks indicate with the direct and indirect bandgaps about the orthorhombic SnS nanowire arrays.

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Optical properties of single-crystalline α-Si3N4 nanobelts

Applied Physics Letters ◽

10.1063/1.1862753 ◽

2005 ◽

Vol 86 (6) ◽

pp. 061908 ◽

Cited By ~ 65

Author(s):

Ligong Zhang ◽

Hua Jin ◽

Weiyou Yang ◽

Zhipeng Xie ◽

Hezhuo Miao ◽

...

Keyword(s):

Optical Properties ◽

Single Crystalline

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Optical Properties of Spin-Coated TiO2Antireflection Films on Textured Single-Crystalline Silicon Substrates

International Journal of Photoenergy ◽

10.1155/2015/147836 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 6

Author(s):

Ryosuke Watanabe ◽

Yohei Eguchi ◽

Takuya Yamada ◽

Yoji Saito

Keyword(s):

Optical Properties ◽

Crystalline Silicon ◽

Low Cost ◽

Incident Light ◽

Antireflection Coating ◽

Silicon Wafers ◽

Reflectance Spectra ◽

Visible Range ◽

Single Crystalline Silicon ◽

Single Crystalline

Antireflection coating (ARC) prepared by a wet process is beneficial for low cost fabrication of photovoltaic cells. In this study, we investigated optical properties and morphologies of spin-coated TiO2ARCs on alkaline textured single-crystalline silicon wafers. Reflectance spectra of the spin-coated ARCs on alkaline textured silicon wafers exhibit no interferences and low reflectance values in the entire visible range. We modeled the structures of the spin-coated films for ray tracing numerical calculation and compared numerically calculated reflectance spectra with the experimental results. This is the first report to clarify the novel optical properties experimentally and theoretically. Optical properties of the spin-coated ARCs without interference are due to the fractional nonuniformity of the thickness of the spin-coated ARCs that cancels out the interference of the incident light.

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