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

2007 ◽  
Vol 7 (12) ◽  
pp. 4421-4427 ◽  
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.

Hierarchical ZnO Nanostructures: Growth and Optical Properties

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.

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

2012 ◽  
Vol 26 (27) ◽  
pp. 1250176 ◽  
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).

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

2007 ◽  
Vol 7 (12) ◽  
pp. 4522-4528 ◽  
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.

The effect of induced strains on photoluminescence properties of ZnO nanostructures grown by thermal evaporation method

2016 ◽  
Vol 30 (07) ◽  
pp. 1650081 ◽  
Author(s):  
Yaser Arjmand ◽  
Hosein Eshghi
Keyword(s):  
Main Parameter ◽  
Morphological Study ◽  
Thermal Evaporation ◽  
Zinc Powder ◽  
Hexagonal Structure ◽  
Optical Data ◽  
Metallic Zinc ◽  
Zno Nanostructures ◽  
Photoluminescence Properties ◽  
Thermal Evaporation Method

In this paper, ZnO nanostructures have been synthesized by thermal evaporation process using metallic zinc powder in the presence of oxygen on [Formula: see text]-Si (100) at different distances from the boat. The structural and optical characterizations have been carried out. The morphological study shows various shape nanostructures. XRD data indicate that all samples have a polycrystalline wurtzite hexagonal structure in such a way that the closer sample has a preferred orientation along (101) while the ones farther are grown along (002) direction. From the structural and optical data analysis, we found that the induced strains are the main parameter controlling the UV/green peaks ratios in the PL spectra of the studied samples.

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

2006 ◽  
Vol 957 ◽  
Author(s):  
Ahmad Umar ◽  
Q. Ahsanul Haq ◽  
Sang Hoon Kim ◽  
Yeon Ho Im ◽  
Yoon Bong Hahn
Keyword(s):  
Optical Properties ◽  
Substrate Surface ◽  
Hexagonal Phase ◽  
Zinc Powder ◽  
Metal Catalyst ◽  
Single Crystalline ◽  
Morphological Studies ◽  
Wurtzite Hexagonal Phase ◽  
Photoluminescence Studies ◽  
Source Materials

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.

Synthesis of ZnO Nanostructures by Thermal Evaporation on Graphite

2007 ◽  
Vol 124-126 ◽  
pp. 575-578
Author(s):  
Kon Bae Lee ◽  
Ki Seop Cho ◽  
Won Hee Lee ◽  
Hoon Kwon
Keyword(s):  
Temperature Region ◽  
Thermal Evaporation ◽  
Metal Catalyst ◽  
Zno Nanostructures ◽  
Zno Nanowire ◽  
Zno Particles ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Zno Powder ◽  
Lower Temperature Region

ZnO nanostructures have been synthesized on graphite substrates by thermal evaporation of ZnO powder without a metal catalyst at a temperature of 1300. The colors of the as-synthesized products gradually change from white and brown to gray as the distance from the source material increases. ZnO particles were formed at higher temperature region. ZnO particles gradually changed into ZnO nanowire as the temperature decreased. Finally, ZnO nanowires disappeared completely and only Zn particles were observed at lower temperature region.

Substrate Dependent Morphologies and Luminescence Properties of ZnO Nanostructures Prepared by Thermal Evaporation

2009 ◽  
Vol 60-61 ◽  
pp. 278-282 ◽  
Author(s):  
Bin Ping Zhuang ◽  
Fa Chun Lai ◽  
Li Mei Lin ◽  
Ming Bao Lin ◽  
Yan Qu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Thermal Evaporation ◽  
Zinc Powder ◽  
Substrate Material ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
Pure Zinc ◽  
X Ray ◽  
Structure Morphology ◽  
Quartz Substrates

High density ZnO nanostructures were fabricated on Au coated Si and quartz substrates through once and the same oxidative evaporation of pure zinc powder. The coated side of the substrate was intentionally positioned in two directions of face and back to the zinc sources. Structure, morphology and optical properties of the samples were investigated by scanning electron microscopy, X-ray diffraction, Raman spectra and room temperature photoluminescence measurements. The results showed that the samples on the different substrates with different directions have three different morphologies, including film-, rod- and comb-like nanostructures. Photoluminescence spectra of the samples showed the various bands centered in UV (380-390 nm), blue (470-490 nm), green (500-550 nm) and orange (610-620 nm) region. It demonstrates that the substrate material and the direction of substrate significantly affect the growth of ZnO nanostructures.

Growth and photocatalytic properties of one-dimensional ZnO nanostructures prepared by thermal evaporation

2009 ◽  
Vol 44 (10) ◽  
pp. 1954-1958 ◽  
Author(s):  
Hongwei Yan ◽  
Jianbo Hou ◽  
Zhengping Fu ◽  
Beifang Yang ◽  
Pinghua Yang ◽  
...  
Keyword(s):  
Thermal Evaporation ◽  
Photocatalytic Properties ◽  
Zno Nanostructures ◽  
One Dimensional

scholarly journals Влияние режима получения образцов и термообработки на локальную структуру халькогенидного полупроводника Ge-=SUB=-2-=/SUB=-Sb-=SUB=-2-=/SUB=-Te-=SUB=-5-=/SUB=-

2022 ◽  
Vol 56 (3) ◽  
pp. 291
Author(s):  
С.Н. Гарибова ◽  
А.И. Исаев ◽  
С.И. Мехтиева ◽  
С.У. Атаева ◽  
Р.И. Алекперов
Keyword(s):  
Heat Treatment ◽  
Thermal Processing ◽  
Thermal Evaporation ◽  
Amorphous State ◽  
Hexagonal Structure ◽  
Structural Elements ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Matrix ◽  
Close Range

Specifics of "amorphous state - crystal" phase transitions in dependence on the samples obtaining method and thermal processing, as well as changes in the structure and close range order in the arrangement of the atoms of Ge20Sb20.5Te51 chalcogenide semiconductors have been studied by the x-ray diffraction and Raman spectroscopy. It has been shown that Ge20Sb20.5Te51 films obtained by thermal evaporation on an unheated substrate are amorphous; after heat treatment at 220 and 400 °C, transform into a crystalline phase with a cubic and hexagonal structure. The chemical bonds and the main structural elements that form the matrix of the investigated objects, as well as the changes that occur in them during heat treatment, have been determined.

Formation of ZnO nanostructures by a simple way of thermal evaporation

2002 ◽  
Vol 81 (4) ◽  
pp. 757-759 ◽  
Author(s):  
B. D. Yao ◽  
Y. F. Chan ◽  
N. Wang
Keyword(s):  
Thermal Evaporation ◽  
Zno Nanostructures
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