共查询到20条相似文献,搜索用时 15 毫秒
1.
利用稀土金属Tb作为催化剂,通过氨化磁控溅射在Si(111)衬底上的Ga203/Tb薄膜制备出GaN纳米棒.X射线衍射和傅里叶红外吸收谱测试结果表明,制备的样品为六方结构的GaN.利用扫描电子显微镜、透射电子显微镜和高分辨透射电子显微镜对样品进行测试,结果显示样品为单晶结构的纳米棒,直径为80~200 nm,长度达几十微米.最后简单地讨论了GaN纳米棒的生长机制. 相似文献
2.
Jin Chen Jin LiJiahui Li Guoqing XiaoXiaofeng Yang 《Journal of Alloys and Compounds》2011,509(3):740-743
Uniform ZnO nanorods with a gram scale were prepared by a low temperature and solution-based method. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL). The results showed that the sample had uniform rod-like morphology with a narrow size distribution and highly crystallinity. Room-temperature PL spectra of these nanorods show an exciton emission around 382 nm and a negligible deep level emission, indicating the nanorods have high quality. The gas-sensing properties of the materials have been investigated. The results indicate that the as-prepared nanorods show much better sensitivity and stability. The n-type semiconductor gas sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 400 °C. ZnO nanorods are excellent potential candidates for highly sensitive gas sensors and ultraviolet laser. 相似文献
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4.
Yu-Jen HsiaoTe-Hua Fang Liang-Wen JiZhe-Wei Chiu 《Journal of Alloys and Compounds》2011,509(29):7684-7687
The luminescence properties of LiGaO2 microflakes synthesized using the sol-gel process are investigated. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) and absorption spectra. The PL spectra excited at 325 nm have a broad and strong emission band with a peak at 383 nm, which corresponds to the self-activated luminescence of the tetrahedral gallium group. The optical absorption spectra of the sample annealed at 600 °C exhibited a band-gap energy of 3.38 eV. 相似文献
5.
采用射频磁控溅射技术在硅衬底上制备Ga2O3/Nb薄膜,然后在900℃下于流动的氨气中进行氨化制备GaN纳米线.用X射线衍射(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜详细分析了GaN纳米线的结构和形貌.结果表明:采用此方法得到的GaN纳米线有直的形态和光滑的表面,其纳米线的直径大约50nm,纳米线的长约几个微米.室温下以325nm波长的光激发样品表面,只显示出一个位于367 nm的很强的紫外发光峰.最后,简单讨论了GaN纳米线的生长机制. 相似文献
6.
Xinjuan Wang Bingsuo Zou Qinglin ZhangAihua Lei Wenjie ZhangPinyun Ren 《Journal of Alloys and Compounds》2011,509(41):9959-9963
CdS and ZnS nanostructures with complex urchinlike morphology were synthesized by a facile solvothermal approach in a mixed solvent made of ethylenediamine, ethanolamine and distilled water. No extra capping agent was used in the process. The structure, morphologies and optical properties of these nanostructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The as-synthesized urchinlike architectures were composed of nanorods with wurtzite structure. The preferred growth direction of nanorods was found to be the [0 0 1] direction. The PL spectrum of CdS nanostructures exhibited a highly intense red emission band centered at about 706 nm. On the basis of the experimental results, a possible growth process has been discussed for the formation of the CdS and ZnS urchinlike structures. 相似文献
7.
The micron-sized Sr2(P2OT):Ce,Tb green phosphors were prepared by being annealed at different temperatures with its precursors synthesized by co-pre-cipitates of (NH4)2HPO4 at ambient temperature. The phase structure, grain size, surface morphology, and luminescent properties of phosphors were investigated by X-ray diffraction, scanning electron microscope, trans-mission electron microscope, and fluorescence spectrum. The results show that the product of precursor annealed at 1,100 ℃ is Sr2(P2O7):Ce,Tb, which belongs to ortho-rhombic phase. The powder is spherical and the size dis-tribution is in micron grade. The sample with the molar ratio of Sr/Tb/Ce of 100.0:0.4:0.6 shows the best fluores-cence effect annealed at 1,100 ℃ for 3 h. The phosphors produce green fluorescence by being excitated with ultra-violet radiation of 254 nm wavelength, and the main emission peak is at 547 nm. The Sr2(P2O7):Ce,Tb phos-phors synthesized by co-precipitation method of precursors at ambient temperature is a kind of efficient green-emitting phosphors. 相似文献
8.
SnO_2空心球的水热制备与表征 总被引:1,自引:0,他引:1
采用简单的水热法制备了SnO_2空心球.通过FE-SEM、TEM、TG-DTA、XRD对其微观形貌、结构、相组成等进行了表征和分析, 对SnO_2空心微球的荧光特性进行了初步探索.结果表明,所得SnO_2空心球是由纳米晶粒组成的多晶结构,壁厚约为15 nm,微球平均直径约为125 nm.产物在550 ℃热处理后为四方晶体结构的SnO_2,荧光光谱分析表明,SnO_2空心球分别在470、818 nm处产生PL特征峰,主要由于缺陷形成杂质带导致. 相似文献
9.
将由Zn(CH3COO)2·2H2O和Na2CO3通过室温研磨反应获得的前驱体在PEG400存在下于240°C热分解获得大量的ZnO六棱锥产物。用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)表征产物的晶体结构和形貌。进一步的实验结果表明:PEG400在ZnO六棱锥形成过程中发挥着重要作用,单六棱锥和双六棱锥的结构差异来自于热分解反应。光致发光谱(PL)测试表明:ZnO六棱锥在386nm处展示强的近带隙发射,在550nm处展示较弱的绿光发射。435cm-1处的拉曼振动表明ZnO六棱锥具有良好的晶体质量。 相似文献
10.
利用碳纳米管通过碳热法合成了氧化镓纳米线、纳米带和纳米片。采用扫描电镜和透射电镜对其进行了形态和结构表征。合成的氧化镓纳米结构是单晶体。室温光致发光谱分析发现,氧化镓纳米晶在蓝光区域487nm处产生明显的发射峰。 相似文献
11.
H.I. Abdulgafour F.K.YamZ. Hassan K. AL-HeuseenM.J. Jawad 《Journal of Alloys and Compounds》2011,509(18):5627-5630
Porous silicon (PS) technology is utilized to grow coral reef-like ZnO nanostructures on the surface of Si substrates with rough morphology. Flower-like aligned ZnO nanorods are also fabricated directly onto the silicon substrates through zinc powder evaporation using a simple thermal evaporation method without a catalyst for comparison. The characteristics of these nanostructures are investigated using field-emission scanning electron microscopy, grazing-angle X-ray diffraction (XRD), and photoluminescence (PL) measurements of structures grown on both Si and porous Si substrates. The texture coefficient obtained from the XRD spectra indicates that the coral reef-like nanostructures are highly oriented on the porous silicon substrate with decreasing nanorods length and diameter from 800-900 nm to 3.5-5.5 μm and from 217-229 nm to 0.6-0.7 μm, respectively. The PL spectra show that for ZnO nanocoral reefs the UV emission shifts slightly towards lower frequency and the intensity increase with the improvement of ZnO crystallization. This non-catalyst growth technique on the rough surface of substrates may have potential applications in the fabrication of nanoelectronic and nanooptical devices. 相似文献
12.
T. Al-Harbi 《Journal of Alloys and Compounds》2011,509(2):387-390
Single crystalline Ni-doped ZnO hexagonal nanodiscs are successfully synthesized. Zinc acetate, nickel nitrate, sodium hydroxide and poly (vinyl pyrrolidone) (PVP) were mixed together and transferred to a 100 ml Teflon-lined stainless steel autoclave which kept at 150 °C for 24 h. The morphology and microstructure were determined by field emission scanning electron microscopy (FE-SEM), X-ray diffraction transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and photoluminescence (PL) spectroscopy. The investigation confirmed that the products were of the wurtzite structure of ZnO. The doped hexagonal nanodiscs have edge length 30 nm and thickness of 45 nm. EDX result showed that the amount of Ni in the product is about 12%. Photoluminescence of these doped hexagonal nanodiscs exhibits a blue shift and weak ultraviolet (UV) emission peak, compared with pure ZnO, which may be induced by the Ni-doping. The growth mechanism of the doped hexagonal nanodiscs was also discussed. 相似文献
13.
The large-scale ZnO rods of submicrometer were prepared on the bare glass using a wet chemical method under different experimental parameters, such as the reactant concentration and the growth time. The microstructure of the ZnO rods was characterized by X-ray diffractometry(XRD) and field emission scanning electron microscopy (FESEM) with the energy dispersive X-ray spectroscopy(EDX), and the optical property was investigated by the room-temperature photoluminescence (PL) spectra. XRD and FESEM results show that the wurtzite structure and rod-like ZnO is obtained. The length (3-8 μm) and the diameter (400 nm- 3 μm) vary with the experimental parameters. A strong UV emission at 384 nm and a weak visible yellow-green emission around 570 nm are observed in the PL spectrum. After annealing at 600 ℃ in air, the UV peak intensity increases obviously and the yellow-green peak intensity decreases greatly. The near-band-edge UV emission is attributed to the exciton recombination; the yellow-green emission can be associated with the defect recombination; and some defect complexes may be responsible for the latter emission. 相似文献
14.
采用射频等离子体辅助分子束外延 (RF-MBE)技术在蓝宝石衬底上,外延生长了发光波长位于407 nm的InGaN量子点结构,研究了InN成核层技术对其结构和光学特性的影响。材料生长过程中采用反射式高能电子衍射 (RHEED)进行了在位检测,通过原子力显微镜 (AFM),光致发光 (PL)等测试手段表征了InGaN量子点材料的结构和光学特性。结果表明,相对于直接在GaN层上自组织生长InGaN量子点,通过InN成核层技术可以获得高密度、高质量的InGaN量子点结构,量子点尺寸分布更加均匀,主要集中在35~45 nm之间;量子点的密度更高,可以达到3.2×1010/cm2;InN成核层上生长的InGaN量子点的PL发光峰强度为直接在GaN层上生长的InGaN量子点的2倍,发光峰的半高宽较窄,为10 nm 相似文献
15.
利用热壁化学气相沉积在Si(111)衬底上获得GaN晶环,采用扫描电镜(SEM)、选择区电子衍射(SAED)、X射线衍射(XRD),光致发光(PL)谱和傅里叶红外吸收谱(FTIR)对晶环的组成、结构、形貌和光学特性进行分析。初步结果证明:在Si(111)衬底上获得择优生长的六方纤锌矿结构的GaN晶环。SEM显示在均匀的薄膜上出现直径约为10μm的5品环,由XRD和SAED的分析证实晶环呈六方纤矿多晶结构,FTIR显示GaN薄膜的主要成分为GaN,同时含有少量的C污染,PL测试表明晶环呈现不同于GaN薄膜的发光特性。 相似文献
16.
Structural, microstructural, and optical properties of the undoped and Fe-doped zinc oxide (ZnO) thin films grown by spray pyrolysis technique using zinc nitrate as a host precursor have been reported here. X-ray diffraction spectra confirm that all the films have stable wurtzite structure and the effects of Fe dopants on the diffraction patterns have been found to be in agreement with the Vegard’s law. Scanning electron microscopy results show good uniformity and dense surface having spherical-shaped grains. Energy dispersive x-ray analyses with elemental mapping of the Fe-doped films show that the Fe dopants are incorporated homogeneously into the ZnO film matrix. The x-ray photoelectron spectroscopy spectra confirm the presence of 3+ oxidation state of Fe in the doped films. Atomic force microscopy analyses clearly show that the average surface roughness and the grain size decrease with the addition of Fe dopants. Optical studies reveal that the optical band gap value decreases on Fe doping. The 1 at.% Fe-doped film shows normal dispersion for the wavelength range 450-700 nm. The PL spectra of the films show a strong ultraviolet emission centered at ~388 nm in the case of 1 at.% Fe-doped film. A slow photo current response in the films has been observed in the transient photoconductivity measurement. 相似文献
17.
Heesun Yang 《Metals and Materials International》2006,12(4):351-355
Nanorods of S2− rich CdS were synthesized by a reaction of excess S versus Cd precursors in the presence of ethylene diamine. The photoluminescence
(PL) emission from the S2− rich CdS nanorods was broad with a peak at ∼710 nm, which was 40 nm longer in wavelength than the PL peak from Cd2+ rich CdS (∼670 nm) nanorods. The influence of surface electron or hole trap states on the luminescent pathway of CdS nanorods
will be discussed to explain these shifts in wavelength. Nanocrystals of Au ∼2 nm in size were grown on S2− rich surfaces of CdS nanorods. Significant luminescence quenching was observed from the Au nanocrystals on the CdS nanorods
due to interfacial charge separation. Change separation by the Au nanocrystals on the CdS resulted in enhanced photocatalytic
degradation of Procion red mix-5B (PRB) dye in an aqueous solution under UV light irradiation. 相似文献
18.
NOUET Gérard 《稀有金属(英文版)》2006,25(Z2)
Thick GaN layer deposited by hydride vapor phase epitaxy (HVPE) on a metalorganic chemical vapor deposition (MOCVD) GaN template with a thin low temperature (LT) AlN intermediate layer was investigated.High resolution X-ray resolution diffraction (HRXRD) shows that the crystalline quality of thick GaN layer was improved compared with the template.As confirmed by atomic force microscopy (AFM) observations, the surface morphology of AlN intermediate layer helps to improve the nucleation of GaN epilayer.Photoluminescence (PL) spectra measurement shows its high optical quality and low compressive stress, and micro Raman measurement confirms the latter result.Thus, the deposition of the LT-AlN interlayer has promoted the growth of an HVPE-GaN layer with an excellent crystalline quality. 相似文献
19.
Synthesis of ZnS nanoparticles via hydrothermal process assisted by microemulsion technique 总被引:2,自引:0,他引:2
Jun Liu Junfeng Ma Ye Liu Zuwei Song Yong Sun Jingrui Fang Zhensen Liu 《Journal of Alloys and Compounds》2009,486(1-2):L40-L43
Uniform and spherical ZnS nanoparticles with a diameter of 5–10 nm were successfully synthesized at 160 °C via a facile hydrothermal process, where ZnS precursors were prepared by a microemulsion technique. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescent (PL) spectra techniques, respectively. The results showed that the hydrothermal temperature exerted a more important effect than the holding time on the crystallization of ZnS crystallites. The as-prepared ZnS nanoparticles exhibited higher PL intensity than that of the normal ones of micrometer scale besides an obvious blue shift. 相似文献
20.
Tun-Yuan Chiang Ching-Liang Dai Der-Ming Lian 《Journal of Alloys and Compounds》2011,509(18):5623-5626
This study investigates the effect of growth temperature on the optical and structural properties of ultrathin ZnO films on the polished Si substrate. Thickness of the ultrathin ZnO films deposited by atomic layer deposition (ALD) method was about 10 nm. Photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM) techniques were used to measure the properties of ultrathin ZnO films. Experimental results showed that the ultrathin ZnO film deposited at 200 °C had excellent ultraviolet emission intensity, and the average roughness of the film surface was about 0.26 nm. 相似文献