Formation of ZnO nanostructures by a simple way of thermal evaporation

Zinc oxide (ZnO) is a metal oxide material that is interested in research due to its possibility of bandgap tailoring, doping with various types of materials as well as being able to form many structures from zero-dimensional to three-dimensional structures. All these properties allow ZnO to be used in broad applications. Several research studies have been reported on the synthesis of ZnO nanostructures by the physical vapour deposition (PVD) technique. One of the potential PVD technique is thermal evaporation process. Generally, the technique is used to grow thin-film but researchers have found a potential to be used in the growth of nanostructures due to the ability to provide high crystallinity with homogeneous and uniform nanostructures. This analysis will therefore explore more about the thermal evaporation synthesized ZnO nanostructures and the application as photocatalyst material in wastewater treatment.

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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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EFFECT OF W-DOPING ON MORPHOLOGY, STRUCTURAL AND OPTICAL PROPERTIES OF ZnO NANOSTRUCTURES SYNTHESIZED VIA THERMAL EVAPORATION

Modern Physics Letters B ◽

10.1142/s021798491250176x ◽

2012 ◽

Vol 26 (27) ◽

pp. 1250176 ◽

Cited By ~ 1

Author(s):

HOSEIN ESHGHI ◽

YASER ARJMAND

Keyword(s):

Room Temperature ◽

Thermal Evaporation ◽

Hexagonal Structure ◽

Zno Nanostructures ◽

Structural And Optical Properties ◽

Thermal Evaporation Method ◽

Violet Emission ◽

Pl Spectra ◽

Uv Emission ◽

Oxygen Gas

Undoped and W -doped ZnO nanostructures were prepared by heating Zn and WO 3 powders in the presence of oxygen gas without any catalyst, using the thermal evaporation method at 950°C. Samples were characterized by FESEM images, also EDS, XRD and PL spectra. FESEM images showed the formation of nanowires in the undoped sample and porous nanostructures as flat-surface granules with various sizes in the doped samples. XRD spectra of the samples confirmed the formation of wurtzite hexagonal structure with (002) as the preferred orientation, while its intensity has reduced as the doping concentration has increased. Meanwhile, the room temperature PL spectra have indicated this variation is in conjunction with the reduction in the intensity of UV emission and appearance of a violet emission at 420 nm (2.95 eV).

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Synthesis of ZnO Nanostructures by Thermal Evaporation on Graphite

Solid State Phenomena - Advances in Nanomaterials and Processing ◽

10.4028/3-908451-31-0.575 ◽

2007 ◽

pp. 575-578

Author(s):

Kon Bae Lee ◽

Ki Seop Cho ◽

Won Hee Lee ◽

Hoon Kwon

Keyword(s):

Thermal Evaporation ◽

Zno Nanostructures

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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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Zno Nanostructures Grown By Thermal Evaporation And Thermal Decomposition Methods

Nanostructured Materials for Advanced Technological Applications - NATO Science for Peace and Security Series B: Physics and Biophysics ◽

10.1007/978-1-4020-9916-8_21 ◽

2009 ◽

pp. 211-214

Author(s):

F. Kyriazis ◽

S. N. Yannopoulos ◽

A. Chrissanthopoulos ◽

S. Baskoutas ◽

N. Bouropoulos

Keyword(s):

Thermal Decomposition ◽

Thermal Evaporation ◽

Decomposition Methods ◽

Zno Nanostructures

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Growth and microstructural characterization of catalyst-free ZnO nanostructures grown on sapphire and GaN by thermal evaporation

Journal of Materials Research ◽

10.1557/jmr.2007.0108 ◽

2007 ◽

Vol 22 (4) ◽

pp. 937-942 ◽

Cited By ~ 12

Author(s):

Bo Hyun Kong ◽

Hyung Koun Cho

Keyword(s):

Electron Microscopy ◽

Thermal Evaporation ◽

Lattice Mismatch ◽

Zno Nanorods ◽

Microstructural Characterization ◽

Zno Nanostructures ◽

Zno Film ◽

Sapphire Substrates ◽

Transmission Electron ◽

Relationship Of

ZnO nanostructures were grown directly on sapphire substrates and GaN epilayers by thermal evaporation. Their morphologies and densities were found to be strongly dependent on the synthesis position and the kinds of substrate loaded into the reactor due to the different oxygen densities and the lattice mismatch, respectively. Scanning electron microscopy and transmission electron microscopy studies revealed that ZnO nanorods on sapphire substrates grew in four directions, one 〈0001〉Sapphire and three (1014)Sapphire directions. It was found that the in-plane lattice mismatch of inclined ZnO nanorods was remarkably reduced by forming the planar relationship of (0002)ZnO//(1014)Sapphire, compared to that of (1120)ZnO//(1010)Sapphire in the ZnO film. On the other hand, for the GaN epilayers, vertically well-aligned ZnO nanorods were grown after growing an epitaxial ZnO film due to reduced lattice mismatch. Electron energy-loss spectroscopy data showed that Zn-rich stoichiometry was responsible for the formation of ZnO nanostructures.

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Synthesis and luminescence properties of novel ZnO nanostructures: micro and nanospheres, polyhedral cages, tetra-pods, needles, tipped nanorods, nanowires and other “microphone–shaped” structures

MRS Proceedings ◽

10.1557/proc-0900-o06-18 ◽

2005 ◽

Vol 900 ◽

Author(s):

Aurangzeb Khan ◽

Wojciech M Jadwisienczak ◽

Martin E Kordesch

Keyword(s):

Thermal Evaporation ◽

Deep Level ◽

Graphite Powder ◽

Near Band Edge ◽

Zno Nanostructures ◽

Hollow Nanospheres ◽

Green Band ◽

Powder Mixtures ◽

Unique Shape ◽

Nitrogen Flows

ABSTRACTNovel ZnO nanostructures such as hollow nanospheres, nano-cages, nanoneedles, tetra-pods, nanowires, aligned nanorods and nanotubes are synthesized via thermal evaporation of ZnO and graphite powder mixtures in reduced oxygen atmosphere in the presence of argon and nitrogen flows. The ZnO nanostructures, especially nanospheres, have a unique shape and are hollow inside with walls densely decorated with aligned nanowires. Photoluminescence of synthesized ZnO structures measured at 300 K exhibits a strong near band edge peak at ∼380 nm and deep level green band centered at ∼550 nm. Fabricated ZnO structures can be studied for various applications in optoelectronics and sensors.

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