反应磁控溅射ZnO/MgO多量子阱的光致荧光光谱分析

采用反应射频磁控溅射方法，在Si(001)基片上制备了具有高c轴择优取向的ZnO/MgO多量子阱.利用X射线反射、X射线衍射、电子探针，光致荧光光谱等表征技术，研究了ZnO/MgO多量子阱的结构、成份和光致荧光特性.研究结果表明，多量子阱的调制周期在1.85—22.3 nm之间，所制备的多量子阱具有量子限域效应，导致了室温光致荧光峰的蓝移，并观测到了量子隧穿效应引起的荧光效率下降.建立了基于多声子辅助激子复合跃迁理论的室温光致荧光光谱优化拟合方法，通过室温光致荧光光谱拟合发现，ZnO/MgO比ZnO/ZnMgO多量子阱具有更大的峰位蓝移，探讨了导致光致荧光光谱展宽的可能因素. 关键词： ZnO/MgO 多量子阱 磁控溅射 光致荧光 量子限域效应     

纳米β-FeSi2/a-Si多层膜室温光致发光分析

采用射频磁控溅射的方法,在Si（100）基片上制备了纳米β-FeSi₂/Si多层结构,利用X射线衍射、透射电子显微镜、光致发光光谱等表征技术,研究了β-FeSi₂/Si多层结构的结构、成分和光致发光特性.研究结果表明：利用磁控溅射法得到的Fe/Si多层膜,室温下能够检测到β-FeSi₂的1.53 μm处光致发光信号;未退火时多层膜是（非晶的FeSi₂+β-FeSi₂颗粒）/非晶Si结构,退火后则是 关键词： 2')" href="#">β-FeSi₂ 磁控溅射 XRD 光致发光光谱     

有机量子阱的光学性质

采用多源有机分子气相沉积系统(OMBD)制备了Alq₃，PBD/Alq₃，PBD/Alq₃/PBD单层、双层以及量子阱结构，利用电化学循环伏安法和吸收光谱、荧光光谱研究了量子阱的类型和样品的光致发光特性.电化学循环伏安法和吸收光谱的测量结果表明，PBD/Alq₃有机量子阱为Ⅰ型量子阱结构.荧光光谱的研究结果表明，单层Alq₃的光致发光峰不随Alq₃厚度变化而变化；但是双层PBD/Alq₃结构光致发光峰随Alq₃厚度的减小而发生蓝移；同样对于PBD/Alq₃/PBD量子阱结构光致发光峰随Alq₃厚度的减小而发生蓝移.对引起光谱蓝移的原因进行了讨论. 关键词： 有机量子阱 光谱蓝移     

蓝宝石基片的处理方法对ZnO薄膜生长行为的影响

采用反应射频磁控溅射方法,在经过不同方法处理的蓝宝石基片上,在同一条件下沉积了ZnO薄膜.利用原子力显微镜、X射线衍射、反射式高能电子衍射等分析技术,对基片和薄膜的结构、表面形貌进行了系统表征.研究结果显示,不同退火条件下的蓝宝石基片表面结构之间没有本质的差异,均为α-Al₂O₃ (001)晶面,但基片表面形貌的变化较大.在不同方法处理的蓝宝石基片上生长的ZnO薄膜均具有高c轴取向的织构特征,但薄膜的表面形貌差异较大.基片经真空退火处 关键词： ZnO薄膜 反应磁控溅射 基片处理 形貌分析     

CBP/Alq3有机量子阱结构的光致发光

采用多源有机分子气相沉积系统(OMBD)制备了CBP/Alq₃有机多量子阱结构,利用电化学循环伏安特性和吸收光谱、小角X射线衍射、荧光光谱研究了量子阱的能带、结构和光致发光的特性。电化学循环伏安特性和吸收光谱的测量结果表明,CBP的最低占据分子轨道(LUMO)与最高占据分子轨道(HOMO)的位置分别为-2.74,-6.00eV,Alq₃的LUMO与HOMO的位置分别为-3.10,-5.80eV,所以CBP/Alq₃有机量子阱为Ⅰ型量子阱结构。小角X衍射测量显示,在小角的位置(2θ的范围在0°～3°)观察到了对应于量子阱结构的多级布拉格衍射峰,表明多层量子阱结构是有序的层状结构,界面比较完整,界面质量比较好。荧光光谱的研究结果表明,Ⅰ型量子阱结构可以有效地把能量从垒层传递给阱层,从而增强了阱层材料的发光。阱层的厚度对发光峰的位置影响很大,随阱层厚度减小,阱层材料的发光峰出现蓝移现象。并对引起发光峰蓝移的原因进行了讨论。     

m面蓝宝石上ZnO/ZnMgO多量子阱的制备及发光特性研究

利用等离子体辅助分子束外延设备(P-MBE)在m面的蓝宝石(m-Al₂O₃)衬底上制备了ZnO/Zn_0.85Mg_0.15O多量子阱.反射式高能电子衍射谱(RHEED)图样的原位观察表明,多量子阱结构是以二维模式生长的.从光致发光谱中可以看到ZnO/Zn_0.85Mg_0.15O多量子阱在室温仍具有明显的量子限域效应.在290 K时阱宽为3 nm的ZnO/Zn_{0.85关键词： 等离子体辅助分子束外延 ZnO多量子阱 光致发光}     

磁控溅射制备ZnO薄膜及其声表面波特性

通过射频磁控溅射技术在GaAs，Au/GaAs，Si和玻璃基片上成功制备了ZnO多晶薄膜，利用X射线衍射对ZnO薄膜的取向、结晶性进行了表征，结果表明ZnO薄膜呈完全c轴取向，Au缓冲层可以有效地改善ZnO薄膜的晶体质量，X射线摇摆曲线结果表明ZnO(002)衍射峰的半高宽仅为2.41°，同时发现Au缓冲层的结晶质量对ZnO薄膜的c轴取向度有很大影响，通过扫描电子显微镜对ZnO/GaAs和ZnO/Au/GaAs薄膜的表面形貌进行了观测，利用网络分析仪对IDT/ZnO/GaAs薄膜的声表面波特性进行了测量. 关键词： ZnO薄膜 X射线衍射 声表面波     

有机多层量子阱结构的光致发光特性的研究

采用多源高真空有机分子束沉积系统(OMBDs),将两种有机小分子材料PBD和Alq₃以交替生长的方式,制备了不同厚度的PBD/Alq₃有机多层量子阱结构(OMQWs), 并利用电化学循环伏安法和光吸收分别测定了PBD和Alq₃的最低空分子轨道(LUMO)和最高占据分子轨道(HOMO)。该结构类似于无机半导体中的Ⅰ型量子阱结构,PBD层作为势垒层,Alq3层作为势阱层和发光层,并进行了小角X射线衍射(XRD)的测量。利用荧光光谱研究了OMQWs光致发光(PL)特性,得到随着阱层厚度的降低,光致发光的峰位将蓝移;同时随垒层厚度的减小,PBD的发光峰逐渐消失。利用量子阱结构可以使PBD的能量有效的传递给Alq₃,从而增强Alq₃的发光。     

4.48 nm正入射软X射线激光用Cr/C多层膜高反射镜的研制

针对4.48nm类镍钽软X射线激光及其应用实验,设计制备了工作于这一波长的近正入射多层膜高反射镜。选择Cr/C为制备4.48nm高反射多层膜的材料对,通过优化设计,确定了多层膜的周期、周期数以及两种材料的厚度比。模拟了多层膜非理想界面对高反射多层膜性能的影响。采用直流磁控溅射方法在超光滑硅基片上实现了200周期Cr/C多层膜高反射镜的制备。利用X射线衍射仪测量了多层膜结构,在德国BessyⅡ同步辐射上测量了在工作波长处多层膜反射率,测量的峰值反射率达7.5%。对衍射仪测量的掠入射反射曲线和同步辐射测量的反射率曲线分别进行拟合,得到的粗糙度和厚度比的结果相近。测试结果表明,所制备的Cr/C多层膜样品结构良好,在指定工作波长处有较高的反射峰,达到了设计要求。     

有机多层量子阱的能量转移

采用多源有机分子气相沉积系统制备了不同类型的有机多量子阱结构，利用电化学循环伏安法和吸收光谱、荧光光谱研究了量子阱的类型、光致发光的特性.电化学循环伏安法和吸收光谱的测量结果表明，PBD/8-羟基喹啉铝(Alq₃)有机量子阱为Ⅰ型量子阱结构，NPB/Alq₃和BCP/Alq₃有机量子阱为Ⅱ型量子阱结构.荧光光谱的研究结果表明，PBD/Alq₃和BCP/Alq₃量子阱结构可以实现PBD，BCP向Alq₃能量完全转移，而NPB/Alq₃量子阱结构，NPB和Alq₃之间只是部分能量转移.文中对影响能量转移的因素进行了讨论. 关键词： 有机量子阱 能量转移     

Particulars of studying the roughness of substrates for multilayer X-ray optics using small-angle X-ray reflectometry,atomic-force,and interference microscopy

The abilities of standard methods for rough surface investigation are analyzed in case of supersmooth substrates for multilayered X-ray optics. The X-ray specular reflection technique is shown to be the most adequate one. X-ray diffuse scattering and AFM can be applied only in a case of PSD-function calculation and approximation over the entire spectrum range of spatial frequencies.     

Red luminescence in ZnO films prepared by a glycol-based Pechini method

ZnO thin films on fused quartz substrates were prepared by a glycol-based Pechini method. The structural and optical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical transmittance spectrum, and photoluminescence (PL) spectrum. A red emission around 700 nm was found in PL spectrum, and its peak intensity gained a strong enhancement (140%) while annealing temperature increased from 700 °C to 800 °C. The red emission was ascribed to the possible high defect density in boundary layers of nanocrystalline grains.     

Soft X-ray measurements of solid fabry-perot etalons

Soft X-ray measurements of the reflected spectrum from Fabry-Perot etalons were made using the Stanford Synchrotron Radiation soft X-ray beam lines. Each etalon was formed two layered synthetic microstructures (LSM) separated by a carbon spacer (etalon cavity). The etalons were formed using sputter deposition techniques on Si wafer substrates. Two such etalons were tested, each having LSM mirrors consisting of 10 layer pairs of W (20 Å) and (31 Å) and spacer thicknesses of 620 Å and 155 Å, respectively. The measured responses of the etalons is compared with calculations. The qualitative agreement is very good but the reflected spectrum is only about50% of the calculated value. Interfacial roughness, substrate figure, and X-ray beam divergence can easily account for this discrepancy.     

A novel fabrication of superhydrophobic surfaces for universal applicability

The present work reports a novel and facile approach to fabricate stable superhydrophobic surfaces for universal applicability in practice. Poly(furfuryl alcohol)/copper composite coatings were prepared on substrates via a brush-painting method; after being immersed in a stearic acid solution, the superhydrophobic surfaces were obtained due to the formation of copper stearate on the substrates. These products were characterized by field-emission scanning electron microscopy, Fourier transform infrared spectrometry, X-ray powder diffraction and the X-ray photoelectron spectrum. Results demonstrate that the superhydrophobic surfaces formed originally on copper substrates can also be generated on other substrates without the copper element. Furthermore, this work will provide a simple and universal method to create large-scale superhydrophobic surfaces on various substrates.     

Cathodoluminescence and structural studies of nitrided 3D gallium structures grown by MOCVD

Cathodoluminescence (CL) spectrum imaging and grazing incidence X-ray diffraction (GIXRD) are employed to investigate nitride three-dimensional (3D) gallium structures. The metallic precursors are naturally obtained on a large variety of substrates by metal-organic chemical vapor deposition (CVD) with different shape/size controlled by the growth conditions, especially the temperature. These 3D metallic structures are subsequently exposed to a nitridation process in a conventional CVD reactor to form GaN nanocrystals, as confirmed by GIXRD measurements. CL spectroscopy shows visible light emission (2.5-2.8 eV) excited from the GaN in the 3D structures.     

Effects of sapphire substrates surface treatment on the ZnO thin films grown by magnetron sputtering

The surface treatment effects of sapphire substrate on the ZnO thin films grown by magnetron sputtering were studied. The sapphire substrates properties have been investigated by means of atomic force microscopy (AFM) and X-ray diffraction rocking curves (XRCs). The results show that sapphire substrate surfaces have the best quality by CMP with subsequent chemical etching. The surface treatment effects of sapphire substrate on the ZnO thin films were examined by X-ray diffraction (XRD) and photoluminescence (PL) measurements. Results show that the intensity of (0 0 2) diffraction peak of ZnO thin films on sapphire substrates treated by CMP with subsequent chemical etching was strongest, FWHM of (0 0 2) diffraction peak is the narrowest and the intensity of UV peak of PL spectrum is strongest, indicating surface treatment on sapphire substrate preparation may improve ZnO thin films crystal quality and photoluminescent property.     

等离子体增强化学气相沉积法制备含氢类金刚石膜的紫外Raman光谱和X射线光电子能谱研究

利用脉冲辉光放电的方法,在硅片上采用不同的沉积工艺制备了含氢类金刚石膜层,并采用Raman光谱和X射线光电子能谱(XPS)对膜层进行表征.用Raman光谱仪在波长为325 nm的紫外光源的激励下观察膜层的键结构.紫外Raman光谱对含氢类金刚石膜是非常有用的,它能有效避免可见光Raman光谱测量时的荧光干扰,清晰地得到膜层的D峰和G峰.同时利用XPS分析得到膜层的sp3键含量,并与Raman光谱所得数据进行比较.通过Raman光谱和XPS分析可以发现,在紫外光源的激励下,膜层的G峰峰位向高频移方向移动,G峰峰位、I(D)/I(G),G峰半高宽和sp3键含量之间存在一定的关系.     

Synthesis and characterization of GaN nanowires

In this work, GaN nanowires were fabricated on Si substrates coated with NiCl₂ thin films using chemical vapor deposition (CVD) method by evaporating Ga₂O₃ powder at 1100 °C in ammonia gas flow. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and photoluminescence (PL) spectrum are used to characterize the samples. The results demonstrate that the nanowires are single-crystal GaN with hexagonal wurtzite structure. The growth mechanism of GaN nanowires is also discussed.     

金纳米粒子自组装薄膜的光谱学研究

采用柠檬酸钠还原氯金酸制备了金胶体，通过静电自组装制备了金纳米粒子薄膜，利用紫外-可见光吸收光谱等对金纳米粒子薄膜进行了光谱学研究，紫外-可见光吸收光谱表明所制备的金溶胶为单分散体系，根据自组装薄膜的X-射线衍射谱，由谢乐公式估算金纳米粒子的粒径约为21nm；X-射线光电子能谱显示氯金酸的还原反应比较完全，金主要以Au^0的价态存在，金胶体粒子通过静电吸引机制组装到PDDA改性的衬底表面；紫外-可见光吸收光谱和表面增强拉曼光谱显示，由于粒子间的电磁耦合，自组装金纳米粒子薄膜表现出协同等离子体共振吸收行为和表面增强拉曼散射效应。     

MOCVD法生长Ga、P掺杂的ZnO薄膜

采用金属有机化学气相沉积法在蓝宝石衬底上制备Ga、P掺杂的ZnO薄膜,分别采用X射线衍射、扫描电子显微镜、霍尔效应测试、光致发光谱对样品进行表征。通过Ga、P掺杂分别得到n、p型ZnO薄膜,n型ZnO薄膜的载流子浓度可以达到1×1019cm-3,p型ZnO薄膜的载流子浓度达到1.66×1016cm-3。所制备的ZnO薄膜具有c轴择优生长取向,并且p型ZnO薄膜具有较好的光致发光特性。