首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
以溶剂热生长技术(solvothermal technique)制备了半导体CdS的纳米微粒,并采用XRD、TEM、ED对其结构进行表征。在ITO导电玻璃上,采用电化学方法合成聚苯胺薄膜,以提拉的方法将CdS的纳米颗粒涂布其上,自组装得纳米CdS/PANI膜,并以荧光光谱(PL)及非线性Z-扫描法研究其光学特性。实验结果显示:经CdS修饰后,CdS/PANI膜的荧光发射峰强度增强,位置较单一PANI膜移至420nm处,同时经修饰后的复合物膜的非线性光学特性也有显著的提高。  相似文献   

2.
利用光学支架、透镜、滤光片、平移台等在光学面包板上组装了荧光显微镜,组装仪器是集白光照明成像、激光激发荧光成像、荧光光谱探测等功能于一体的开放式系统.利用光学分辨率板白光照明条件下测量了荧光显微镜的空间分辨能力,采集了荧光样品CdTe/CdS量子点的荧光光谱和荧光图像.  相似文献   

3.
亚微观团粒的半导体,是一种引人注目的材料,因其尺寸小而引起量子效应,表现出非同一般的特性.两个研究小组发表了生成特定大小的硫化铜(CdS)团粒的特殊方法. 截径为1-100nm胶状半导体微粒是一类介于孤立分子和固体之间的新材料,可用来研究由分子态向 大块状态的转变.研究表明,胶体半导体的光学性质与宏观晶体截然不同,它依赖于微粒的大小——即所谓量子尺寸效应.微粒咸小时,电子-空穴对受到局域限制,价带和导带中会产生分立的电子态,有效带隙增大,使材料光谱的吸收边发生向短波移动的“蓝移”,光跃迁的振荡强度减弱,还会出现分立的吸收带;…  相似文献   

4.
CdS半导体纳米晶体高强度激发下光谱特性研究   总被引:4,自引:2,他引:2  
窦恺  赵家龙 《发光学报》1995,16(3):278-280
CdS半导体微晶作为代表性介观材料(mesoscopic material)其光学吸收和发光与量子尺寸效应的关系已经得到广泛研究[1-4],发现随着CdS微晶尺寸减小,CdS本征吸收和发射带呈现显著蓝移.Rossetti等人[3]和Y.Wang等人[4]分别通过对溶胶、沸石、聚合物和玻璃中CdS纳米晶体的光致发光测量研究了发光来源以及发光与尺寸的关系,确定了两个宽带发光分别属于带隙发光(350-500nm)和表面态或缺陷发光(500-700nm).本文首次报道了利用溶胶凝胶方法制备的钠硼硅中纳米尺寸CdS晶体高激发功率条件下的发光光谱测量结果,观察到随激发功率增加发光光谱兰移和线宽明显宽化,讨论了其物理机制.  相似文献   

5.
功能性硫化镉纳米粒子荧光增敏法测定诺氟沙星   总被引:3,自引:0,他引:3  
室温条件下在水溶液中以硫代乙酰胺和硝酸镉为原料,采用微波法合成了粒度分布均匀、分散性好的CdS纳米粒子,在pH 7.4时,CdS纳米粒子的荧光强度能够被诺氟沙星增敏,且CdS纳米粒子的荧光光谱显示其带边发射位于495 nm,缺陷发射位于565 nm而且不明显,所以表明合成的CdS纳米粒子的光学性质较好,同时紫外吸收光谱和透射电子显微镜也证明了此推论.同时考察了缓冲液、pH值、离子强度、反应时间和温度等条件因素对CdS纳米粒子-诺氟沙星复合体系荧光光谱特性的影响.探讨了在最佳实验条件下,CdS纳米粒子与诺氟沙星之间的可能作用机理,荧光光谱法显示CdS纳米粒子的增加强度与诺氟沙星浓度成正比,其浓度范围为1.25~11.25μg·mL-1或11.25~100.0μg·mL-1,检测限为1.5×10-3 μg·mL1.该方法为研究诺氟沙星含量测定提供了一种新的思路,同时为研究其在体内代谢提供了一定的指导意义.  相似文献   

6.
核壳结构CdS/ZnS纳米微粒的制备与光学特性   总被引:6,自引:0,他引:6  
用微乳液法制备CdS纳米微粒 ,以ZnS对其进行表面修饰 ,得到具有核壳结构的CdS/ZnS纳米微粒 .采用X射线衍射 (XRD)、透射电镜 (TEM )表征其结构、粒度和形貌 ,紫外 可见吸收光谱 (UV)、光致发光光谱(PL)表征其光学特性 .制得的CdS近似呈球形 ,直径为 3.3nm ;以XRD和UV证实了CdS/ZnS核壳结构的实现 .研究了不同ZnS壳层厚度对CdS纳米微粒光学性能的影响 ,UV谱表明随着壳层厚度的增加纳米微粒的吸收带边有轻微的红移 ,同时短波吸收增强 ;PL谱表明壳层ZnS的包覆可减少CdS纳米微粒的表面缺陷 ,带边直接复合发光的几率增大 ,具有合适的壳层厚度时发光效率大大提高 .  相似文献   

7.
用光声技术研究半导体TiO2,ZnO纳米晶粉的光学特性   总被引:1,自引:0,他引:1  
应用新型的光声光谱技术,研究了不同种类和不同制备工艺条件的半导体纳米晶粉的光学特性,测量了半导体TiO2、ZnO和掺铝ZnO纳米晶粉的光声光谱,获得了这些半导体纳米晶粉的带隙和光谱吸收系数.研究结果表明,相同种类和相同颗粒形状的半导体纳米晶粉的粒径越小,光学吸收系数越大.半导体纳米晶粉的带隙与相同种类纳米颗粒形状(圆球...  相似文献   

8.
赵湘辉  魏爱香  招瑜 《发光学报》2011,32(8):793-797
采用化学水浴以CdCl2·H2O、CS( NH2)2、NH4Cl、NH3·H2O和去离子水作为反应前驱物制备CdS纳米晶薄膜.采用扫描电镜( SEM)、X射线衍射(XRD)、透射光谱和稳态荧光光谱,研究了反应前驱物中不同的n(S)∶n(Cd)对所制备的CdS薄膜的形貌、结构和光学性能的影响.结果表明:反应前驱物中n(S...  相似文献   

9.
采用近空间升华法(CSS)在氩/氧气氛中制备了硫化镉(CdS)多晶薄膜.利用XRD,XPS,AFM,UV-VIS光谱和四探针技术等测试和分析手段系统研究了氧对薄膜的成分、结构、光学和电学等性质的影响.结果表明,用近空间升华法制备的CdS薄膜具有六方相结构,膜层致密、均匀,平均晶粒大小约为40 nm,富硫.氧掺入后部分与镉生成氧化镉,并随着氧含量的增加,薄膜的成分有趋于化学计量比的趋势,光学带隙加宽,光暗电导比增加.此外,还利用扫描电镜(SEM)观察了CdS/CdTe断面结合光谱响应(QE)的结果讨论了氧对CdS/CdTe界面互扩散的影响.发现,随着CdS薄膜制备气氛中氧分压的升高,CdS/CdTe界面的互扩散程度降低,有利于提高器件在500—600 nm波长范围内的光谱响应.认为,氧含量的增加不但使CdS薄膜在光伏应用方面的质量得到改善,而且CdTe太阳电池器件中的CdS/CdTe界面也得到了优化. 关键词: CdS多晶薄膜 近空间升华法 窗口层 界面  相似文献   

10.
CdS/CdMnTe异质结是具有集成分立光谱结构的叠层电池的"核芯"元件,是驱动第三代太阳能电池发展的核心引擎,其界面相互作用对大幅度提高太阳能电池的转换效率至关重要.本文采用基于密度泛函理论的第一性原理计算构建CdS (002), CdMnTe (111)表面模型及Mn原子占据不同位置的CdS/CdMnTe异质结界面结构模型,分析CdS (002), CdMnTe (111)表面及异质结界面的电子性质和光学性质.晶格结构分析表明, CdS/CdMnTe异质结的晶格失配度约为3.5%,弛豫后原子位置与键长均在界面处发生一定程度的变化.态密度分析发现异质结界面的费米能级附近不存在界面态,并且界面处的Cd, S, Te原子之间的轨道杂化可增强界面的结合能力.差分电荷密度分析显示,界面处发生了电荷的重新分配,电子由CdMnTe转移到CdS侧.光学分析显示, CdS/CdMnTe异质结主要吸收紫外光,吸收系数可达105 cm~(–1),但不同Mn原子位置的异质结光学性质也稍有差别.在200—250 nm范围, Mn原子位于中间层的异质结的吸收系数更大,但在250—900 nm范围内, Mn原子位于界面层的异质结吸收峰更高.本文合理构建了CdS/CdMnTe异质结模型,计算分析了其界面光电性能,可为提高叠层电池的光电转换效率提供一定的理论参考,为实现多带隙异质结的实验研究提供一定的理论依据.  相似文献   

11.
The optical nonlinearity of a CdTe quantum dot enhanced by a gold nanoparticle has been theoretically studied by employing the multi-bands effective mass method. The energy levels have been computed using 6×6 k.p model for the valence band. The semiconductor quantum dot-size-dependent third-order susceptibility of third harmonic generation in a CdTe-Au nanocrystal complex has been analyzed. It is found that the metal nanoparticle enhances the optical nonlinearity of the semiconductor quantum dot due to the dipole/multipole interaction that will bring in the strong damping and the field enhancement. By choosing the radius of CdTe quantum dot, the third-order nonlinear susceptibility for third harmonic generation can be optimized for the one- and multi-photon resonance. Also, we can alter the optical nonlinearity by changing the ratio of semiconductor-metal nanoparticle distance to the metal nanoparticle radius.  相似文献   

12.
The third-order optical nonlinearity of Ag-O-Cs thin films, where Ag nanoparticles are embedded into a CsxO semiconductor matrix, was measured by the femtosecond optical Kerr technique. The third-order nonlinear optical susceptibility, χ(3), of the thin films was estimated to be 1.1×10-9 esu at the incident wavelength of 820 nm. The response time, i.e. the full width at half-maximum of the Kerr signal, is as fast as 114 fs only. The intrinsic third-order optical nonlinearity can be attributed to the intraband transition of electrons from the occupied state near the Fermi level to the unoccupied state. It is suggested that such a nonlinearity is further enhanced by the local field effect that is present in the metallic nanoparticles composite thin films.  相似文献   

13.
张立军  吴重庆  李亚捷 《光学学报》2007,27(11):1945-1949
全光缓存器能够在光域内对数据包进行缓存,解决数据包在节点的冲突。提出了一种新型可擦写的全光缓存器,该缓存器以半导体光放大器(SOA)为非线性相移器件,利用信号光和控制光在半导体光放大器中的交叉相位调制实现信号在光域内的"写入"和"读出"。在注入信号峰值功率相同的条件下,双半导体光放大器结构的采用还可以对信号光实现功率补偿,比利用单个半导体光放大器进行"写入/读出"控制延长了缓存时间,并能有效克服在数据包"写入"缓存器时造成的输出端口处信号光的泄漏。该缓存器顺利实现了2.5 Gb/s数据包的多圈缓存。  相似文献   

14.
We propose a novel optical signal regeneration system based on wavelength converters by use of cross gain modulationin cascaded semiconductor optical amplifiers. The nonlinearity in optical input/output characteristics and eye opening using NRZ signal were archived.  相似文献   

15.
Optics has already been established its significant application over electronics using the nonlinearity of optical medium. The use of semiconductor optical amplifier (SOA) as a nonlinear medium has remarkably extended in the field of optoelectronic technology due to his high switching speed and high extinction ratio. The SOA based devices are used in multifunctional way mainly in switching, multiplexing, de-multiplexing and wavelength conversion. Here in this paper the authors propose a new demultiplexer scheme with the broad area semiconductor optical amplifier (BSOA) using the frequency encoding techniques and tri state logic. Frequency encoding techniques and tri-state logic in optics are already been established as a potential mechanism.  相似文献   

16.
Maximal optical nonlinearity obtainable in amorphous materials at telecommunication wavelengths of ∼1.5 μm is predicted. Applying a semiconductor concept, we suggest that nonlinear properties become greater in the materials with smaller optical gaps. This trend makes the chalcogenide glass such as As2Se3 promising for fiber devices (∼1 m), including optical switches, intensity stabilizers, and stimulated Raman amplifiers. However, for integrated devices with optical path lengths of ∼1 cm, greater nonlinearity is needed.  相似文献   

17.
Semiconductors have large optical nonlinearity with response speed in the several tens of picosecond range, making them ideal use as all-optical regenerators and wavelength converters. We theoretically and experimentally investigated optical nonlinearities induced by carrier dynamics both in forward biased semiconductor waveguide (SOA) and in reverse biased semiconductor waveguide (EAM). We made a detailed theoretical study of carrier dynamics in semiconductor waveguides by using the newly developed time-dependent transfer matrix method. To confirm the simulation results, we propose utilizing a polarization discriminating delayed interferometer (PD-DI) configuration as a simple technique for measuring optical nonlinearities such as cross gain modulation (XGM), cross absorption modulation (XAM), and cross phase modulation (XPM). In the first part of the paper, we reviewed SOA-based regenerators. As expected from the simulation results, we confirmed that injection of the transparent assist light was very effective in reducing of the SOA gain recovery time of down to a few tens of picoseconds. We further demonstrated 40 Gbit/s regeneration using an SOA-one-arm MZI (so-called UNI) configuration. The superior regeneration capability of two-stage UNI was successfully confirmed by a recirculating loop experiment up to 30,000 km with 150 regenerations. In the latter part of the paper, we reviewed all-optical regenerators using EAM. A bit-synchronized rf-driven XAM 3R regenerator consisting of only one EAM for both gating and timing correction was demonstrated at 20 Gbit/s. An EAM in conjunction with delayed interferometer configuration, which utilizes XPM as well as XAM in the EAM, has structurral simplicity and fast regeneration operability up to 100 Gbit/s. The fast response of EAM allows the optical regeneration with a small pattern word effect.  相似文献   

18.
We show that a giant Kerr nonlinearity with a relatively large cross phase modulation (CPM) phase-shift can be used for realizing polarization quantum phase gate based on the nonlinear optical response in a coupled semiconductor double quantum well (SDQW) structure via intersubband transitions.  相似文献   

19.
The prospects for the enhancement of the third-order optical nonlinearity in the mesoscopic semiconductor structures: quantum wells, wires, and boxes are analyzed. It is shown, that if the structures are designed in such a way that the ground state and the excited states wavefunctions are spatially separated, then the electrostatic Coulomb interactions will result in the enhancement of the optical nonlinearity. The enhancement factor has been analyzed for the structures of different shapes and material compositions. It was found that the possible enhancement factor ranges from 2 for quantum wells to 10 for quantum wires and boxes.  相似文献   

20.
It was found that optical properties and nonlinearity of semiconductor microcrystallites in glass matrix are determined mainly by their structure. We established that the Auger recombination and the traps filling are responsible for the intensity dependence of transmission at picosecond and nanosecond pump respectively. The probabilities of linear and Auger recombination as a function of intensity have been obtained by computer simulation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号