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1.
用化学溶液法以醋酸锌和六亚甲基四胺为原料在玻璃衬底上生长出不同形貌的亚微米和微米ZnO棒。探讨了反应液的酸碱度和反应液浓度对生成的ZnO棒形貌的影响,并分析了其生长机制。通过控制一定的酸碱度和溶液浓度,可以得到规则的六角ZnO棒状阵列。这种规则的六角棒沿着[002]方向生长。测量了样品的XRD,扫描电镜像(SEM),并对其发光性能进行了测量分析。其中规则六角ZnO棒的光致发光光谱中有一很强的峰值650nm红色宽谱带和一峰值约387nm的激子发光峰。激子发光峰加宽,实际上是自由激子的发光峰(380nm)和Zni的发光峰(430nm)的叠加。而红色发光峰可能是Vo2+中的电子和价带中的空穴辐射复合所致。  相似文献   

2.
用硝酸锌(Zn(NO3)2·6H2O)与六亚甲基四胺(C6H12N4)以等浓度配制成反应溶液,通过水浴法制备出了形貌可控的棒状ZnO纳米结构,讨论了不同反应浓度及衬底对ZnO表面形貌的影响.样品的XRD和扫描电子显微镜分析结果表明,所得产物均为六方纤锌矿结构,在有晶种层的衬底上制备出的ZnO纳米棒沿(001)方向并垂直于衬底表面生长.随着反应浓度的增加,ZnO纳米棒的直径增大,长径比减小.样品的场发射性能测试表明,反应溶液浓度为0.005 mol/L,以铜膜为晶种层的硅衬底上制备出的场发射阴极具有较好的场发射性能.  相似文献   

3.
氩气氛常压下,利用热蒸发法,在无催化剂、无ZnO预沉积层的硅衬底上制备了取向良好,排列整齐的ZnO纳米棒阵列.在距Zn源不同位置的Si衬底上得到了不同形貌的样品.硅衬底置于锌源正上方是得到取向一致的ZnO纳米阵列的一个关键性条件.用场发射扫描电子显微镜、X射线粉末衍射表征样品表面形貌、晶体结构.进一步研究了样品的生长机制和荧光性质.  相似文献   

4.
采用两步法,即先用磁控溅射在Si(100)表面生长一层ZnO籽晶层、再利用液相法制备空间取向高度一致的ZnO纳米棒阵列.用扫描电子显微镜、X射线衍射、高分辨透射电子显微镜和选区电子衍射对样品形貌和结构特征进行了表征.结果表明,ZnO纳米棒具有垂直于衬底沿c轴择优生长和空间取向高度一致的特性和比较大的长径比,X射线衍射的(XRD)(0002)峰半高宽只有0.06°,选区电子衍射也显示了优异的单晶特性.光致发光谱表明ZnO纳米棒具有非常强的紫外本征发光和非常弱的杂质或缺陷发光特性. 关键词: ZnO纳米棒阵列 ZnO籽晶层 两步法 液相生长  相似文献   

5.
一步溶液法制备ZnO亚微米晶体棒及其发光性能   总被引:6,自引:3,他引:3       下载免费PDF全文
用硝酸锌(Zn(NO3)2·4H2O)或醋酸锌(Zn(CH3COO)2·2H2O)分别与六亚甲基四胺((CH2)6N4)以等浓度0.005mol/L配制成两种反应溶液,通过化学溶液法在玻璃衬底上生长出ZnO六角型亚微米棒(长5~8μm,直径300~700nm)。测量了样品的XRD和扫描电镜像。经XRD分析,所得样品均为纤锌矿的ZnO六角型晶体。扫描电镜(SEM)像表明,生长时间为3h或5h时,样品为细长条的棒状结构,长径比超过10:1;生长48h后的ZnO亚微米棒的一端被腐蚀成一定深度的ZnO亚微米管。用负离子配位四面体生长模型分析了ZnO亚微米棒的生长机理。ZnO亚微米棒退火前后的光致发光谱表明,退火处理后的发射谱中的紫外峰消失,而红色发光峰红移并且增强(峰值由630nm左右移到710nm),同时它的激发光谱中的室温激子激发峰也增强。  相似文献   

6.
以Zn(NO3)2·6H2O/HMT为反应物,通过低温水热反应过程,在籽晶衬底上制备了ZnO纳米棒,分别用场发射扫描电子显微镜和X射线衍射仪对ZnO纳米棒形貌与晶体结构进行了表征,并研究了不同方法制备的ZnO籽晶层以及籽晶层厚度对ZnO纳米棒形貌及结晶质量的影响.结果表明磁控溅射籽晶衬底上生长的ZnO纳米棒结晶质量最好,而籽晶层的厚度对ZnO纳米棒的垂直取向性有一定的影响.  相似文献   

7.
水热法制备Co掺杂ZnO纳米棒及其光学性能   总被引:3,自引:2,他引:1  
采用水热法在石英衬底上以Zn(CH3COO)2.2H2O和Co(NO3)2.6H2O水溶液为源溶液,以C6H12N4(HMT)溶液作为催化剂,在较低温度下制备了Co掺杂的ZnO纳米棒。采用X射线衍射(XRD)和扫描电子显微镜(SEM)对所生长ZnO纳米棒的晶体结构和表面形貌进行了表征,考察了Co掺杂对ZnO纳米棒微观结构和对发光性能影响的机制。结果表明:Co掺杂的ZnO纳米棒呈六方纤锌矿结构,具有沿(002)面择优生长特性,Co掺杂使ZnO纳米棒的直径变细;同时室温光致发光(PL)谱检测显示Co掺杂ZnO纳米棒具有很强的近带边紫外发光峰,而与深能级相关的缺陷发光峰则很弱。本研究采用水热法在石英衬底上于较低温度下生长出了具有较高光学质量的Co掺杂ZnO纳米棒。  相似文献   

8.
采用化学沉淀法,以硝酸锌和六次亚甲基四胺的水溶液为生长溶液,在涂覆氧化锌晶种层的玻璃衬底上制备了定向生长的氧化锌纳米棒阵列,并研究了添加剂聚乙烯亚胺的浓度对氧化锌纳米棒形貌和结构的影响.X射线衍射和场发射扫描电镜的结果表明,合成的氧化锌纳米棒阵列较为均匀致密,具有六方纤锌矿结构,且有沿(002)晶面择优生长的特性;随着聚乙烯亚胺浓度的增加,氧化锌纳米棒的直径减小,直径分布趋于均匀,且氧化锌纳米棒的形貌也从锥状转变为柱状结构;另外,聚乙烯亚胺的加入对氧化锌的生长速度具有抑制作用,当聚乙烯亚胺的浓度增加至0.012 mol·L-1时,无氧化锌阵列生长.对氧化锌纳米棒阵列进行了拉曼光谱表征,结果表明,随着溶液中聚乙烯亚胺浓度的增加,氧化锌纳米棒的氧空位缺陷减少.最后,对聚乙烯亚胺浓度对氧化锌纳米阵列影响的机理进行了探讨.  相似文献   

9.
利用水热法制备ZnO微米棒。醋酸镁[Mg(CH3COO)2.4H2O]、醋酸锌[Zn(CH3COO)2.2H2O]和六次甲基四胺(C6H12N4)以一定比例配置成反应溶液,把反应溶液加热到90℃,反应时间为24h,能够在硅衬底上生长高质量的ZnO微米棒。用扫描电镜(SEM)和X射线衍射仪对ZnO微米棒的晶体结构和表面形貌进行了分析,结果表明,样品为细长条棒状结构,呈现六方纤锌矿结构,长径比可达10∶1,并且在[002]方向择优生长。在样品中并未发现镁离子,它有可能扮演着催化剂的角色。对ZnO微米棒的光致发光性能进行测量,由PL光谱分析可知,样品在384nm处有一个紫外发光峰,半峰全宽为13nm,紫外发光峰强度比可见发光峰强度大的多,样品的质量较好。  相似文献   

10.
两步溶液法制备亚微米ZnO棒阵列及其退火后的发光   总被引:1,自引:1,他引:0       下载免费PDF全文
通过改变溶液浓度、酸碱度等生长条件,用两步化学溶液沉积法在玻璃衬底上制备出有序排列的亚微米级ZnO棒阵列,棒的截面呈正六边形,直径约为200~500nm。测量了样品的XRD谱和扫描电镜像,证明这些样品都是六方纤锌矿结构的ZnO单晶,且以[002]方向择优生长。将样品退火前后的PL光谱进行比较分析,发现退火后样品的发射光谱中紫外峰消失而长波段的红色发光峰红移并且增强(峰位由630nm左右移到720nm),而其激发光谱中的室温激子激发峰也增强。当退火时间增加到6h后,出现了由430nm的蓝峰和505nm绿峰组成的宽谱带蓝绿色发射。并对发光机理进行了讨论。  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

13.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

14.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

15.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

16.
17.
Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.  相似文献   

18.
A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.  相似文献   

19.
Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.  相似文献   

20.
Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.  相似文献   

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