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1.
Y.H. Kim J.Y. Lee S.-H. Lee J.-E. Oh H.S. Lee 《Applied Physics A: Materials Science & Processing》2005,80(8):1635-1639
Straight and well-aligned GaN nanorods have been successfully synthesized by molecular beam epitaxy (MBE) method. The GaN nanorods have been characterized by field-emission scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). SEM images show that GaN nanorods are constituted with two parts of which shapes are different from each other. The upper part of the nanorod is very thin and its lower part is relatively thick. The XRD and EDS analysis have identified that the nanorods are pure hexagonal GaN with single crystalline wurtzite structure. The TEM images indicate that the nanorods are well crystallized and nearly free from defects. The XRD, HRTEM, and SAED pattern reveal that the growth direction of GaN nanorods is 〈0001〉. The photoluminescence (PL) spectra indicate the good emission property for the nanorods. Finally, we have demonstrated about the two-step growth of the nanorods. PACS 81.07.Bc; 81.05.Ea; 81.15.Hi 相似文献
2.
ZnS nanorods were fabricated by annealing precursor ZnS nanoparticles, which were prepared by one-step, solid-state reaction of ZnCl2 and Na2S through grinding by hand at ambient temperature, in NaCl flux. The as-prepared ZnS nanorods have diameters of 40-80 nm, and lengths up to several micrometers. The structural features and chemical composition of the nanorods were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), and Raman spectra. 相似文献
3.
Scanning electron microscopy (SEM) images, transmission electron microscopy (TEM) images, and selected-area electron diffraction (SAED) patterns showed that vertically well aligned GaN nanorods with c-axis-oriented crystalline wurzite structures were grown on Si(1 1 1) substrates by using hydride vapor phase epitaxy. The high-resolution TEM (HRTEM) images showed that the crystallized GaN nanorods contained very few defects and that they were consisted of , {0 0 0 1}, and { } facets. The formation mechanisms for the GaN nanorods grown on Si(1 1 1) substrates are described on the basis of the SEM, TEM, SAED pattern, and HRTEM results. 相似文献
4.
Highly oriented GaN nanowire arrays have been achieved by the catalytic reaction of gallium with ammonium. The resulting materials
were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), energy dispersive X-ray
spectroscopy (EDS), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM images show
that the resulting materials are nanowire arrays with a uniform length of about 10 μm. XRD, EDS, TEM and SAED indicate that
the nanowire arrays are single-crystal hexagonal GaN with a wurtzite structure. They have diameters of 10 to 20 nm.
Received: 2 October 2002 / Accepted: 7 October 2002 / Published online: 17 December 2002
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ID="*"Corresponding author. E-mail: wwwangjc@sina.com 相似文献
5.
Subhajit Biswas 《Applied Surface Science》2007,253(23):9259-9266
Nanorods and nanosheets of tin sulfide (SnS) were synthesized by a novel thioglycolic acid (TGA) assisted hydrothermal process. The as prepared nanostructures were characterized by X-ray diffraction (XRD) study, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD study reveals the formation of well-crystallized orthorhombic structure of SnS. Diameter of the SnS nanorods varied within 30-100 nm. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) patterns identify the single crystalline nature for the SnS nanocrystals. The mechanism for the TGA assisted growth for the nanosheets and nanorods have been discussed. 相似文献
6.
A new method was applied to prepare GaN nanorods. In this method, gallium oxide (Ga2O3) gel was firstly formed by a sol-gel processing using gallium ethanol, Ga(OC2H5)3, as a new precursor. GaN nanorods were successfully synthesized after annealing of the Ga2O3 gel at 1000 °C for 20 min in flowing ammonia. The as-prepared nanorods were confirmed as single crystalline GaN with wurtzite structure by X-ray diffraction (XRD), selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). Transmission electron microscopy (TEM) displayed that the GaN nanorods were straight and smooth, with diameters ranging from 200 nm to 1.8 μm and lengths typically up to several tens of microns. When excited by 280 nm light at room temperature, the GaN nanorods had a strong ultraviolet luminescence peak located at 369 nm and a blue luminescence peak located at 462 nm, attributed to GaN band-edge emission and the existence of the defects or surface states, respectively. 相似文献
7.
Haiyun Yu Xinyu Song Zhilei Yin Weiliu Fan Xuejie Tan Chunhua Fan Sixiu Sun 《Journal of nanoparticle research》2007,9(2):301-308
The single-crystalline β-FeOOH hollow nanorods with a diameter ranging from 20∼30 nm and length in the range of 70–110 nm
have been successfully synthesized through a two-step route in the solution. The phase transformation and the morphologies
of the hollow β-FeOOH nanorods were investigated with X-ray powdered diffraction (XRD), scanning electron microscopy (SEM),
transmission electron microscopy (TEM), selected area electric diffraction (SAED), high-resolution transmission electron microscopy
(HRTEM), infrared spectrum (IR) and thermo-gravimetric analysis (TGA). These studies indicate that the first step is an incomplete-reaction
course. Furthermore, The formation mechanism of the hollow nanorods has been discussed. It is found that the mixed system
including chitosan and n-propanol is essential for the final formation of the hollow β-FeOOH nanorods. 相似文献
8.
在分子束外延(MBE)系统中, 利用物理气相沉积(PVD)的方法在阳极氧化铝(AAO)模板上制备了有机 染料分子苝四甲酸二酐(PTCDA)的不同纳米结构; 并使用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、 高分辨透射电子显微镜(HRTEM)以及选区电子衍射(SAED)技术进行了系统的研究. 结果发现, 当衬底温度(Ts)为330 ℃时得到的是纳米丝、针、带以及棒; Ts为280 ℃, 230 ℃, 180 ℃时得到的主要是纳米棒, 并且纳米棒的长度随Ts的降低而变短; Ts为50 ℃时只能得到连续的PTCDA薄膜. HRTEM以及SAED结果证实了纳米针与棒为单晶. 依据SEM结果, 提出纳米结构的生成主要受Ts以及衬底表面曲率的影响. 相似文献
9.
S. Senthilkumaar R. Thamiz Selvi 《Applied Physics A: Materials Science & Processing》2009,94(1):123-129
Zinc sulfide nanorods with good photoluminescence have been successfully fabricated using a simple sol-gel process via ultrasonication,
with mercaptoethanol as capping agent. The formation of ZnS nucleation, followed by subsequent growth, is significant in obtaining
highly oriented ZnS nanorods. Temperature, time, and capping agent also proved to be significant factors in the growth of
ZnS nanorods and greatly affect their photo luminescent properties. X-ray diffraction (XRD) analysis, low and high-resolution
transmission electron microscopy (TEM & HRTEM), selected-area electron diffraction (SAED) pattern, and scanning electron microscopy
(SEM) indicated that the ZnS nanorods were single crystal in nature and that they had grown up preferentially along the [0001]
direction. This simple method of nucleation, followed by their successive growth, resulted in the development of an effective
and low-cost fabrication process for high-quality ZnS nanorods with good photo luminescent properties that can be applied
to luminescent sensors and optoelectronic devices. 相似文献
10.
J.Y. Li X.L. Chen Z.Y. Qiao Y.G. Cao M. He T. Xu 《Applied Physics A: Materials Science & Processing》2000,71(3):349-350
Self-aligned GaN nanowire quasi-arrays were synthesized on MgO crystal through a simple gas reaction method. They were characterized
by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy
and high-resolution transmission electron microscopy (HRTEM). FE-SEMimages showed that the product consisted of quasi-arrays
of nanowires. XRD, EDX and HRTEM indicated that the nanowires were wurtzite GaN single crystals.
Received: 19 June 2000 / Accepted: 21 June 2000 / Published online: 9 August 2000 相似文献