薄膜材料与器件

TB43 2004010476 低成本衬底上多晶硅薄膜电池的探索=Polycrystalline silicon thin film solar cells on low cost substrates[刊,中]/许颖(北京市太阳能研究所.北京(100083)),励旭东…∥发光学报.—2003,24(3).—301-304 在低成本,两种纯度的P~( )颗粒硅带衬底(SSP)上,采用RT化学气相沉积(CVD)技术制备了多晶硅薄膜电     

΢�����ӻ�������������廯ѧ����������Ʊ��ྦྷ�象Ĥ

利用微波电子回旋共振等离子体增强型化学气相沉积(ECR-PECVD)采用一步法直接在K9玻璃上低温沉积制备了多晶硅薄膜.研究了不同实验参数对薄膜沉积的影响,采用X射线衍射(XRD)、拉曼光谱、扫描电子显微镜(SEM)等实验分析方法对不同条件下制备的样品进行了晶体结构和表面形貌分析,并讨论了多晶硅薄膜沉积的最佳条件.实验结果表明,玻璃衬底上多晶硅薄膜呈柱状生长,并有一定厚度的非晶孵化层;较高氢气比例和衬底温度有利于结晶,薄膜的结晶率达到了62％;晶粒团簇的最大尺寸约为500nm.     

Raman散射和AFM对多晶硅薄结晶状况的研究

采用等离子体增强化学气相沉积(PECVD)法在普通玻璃衬底上制备了多晶硅(p-si)薄膜。利用拉曼(Raman)散射谱、原子力显微镜(AFM)研究了衬底温度、射频功率和SiH4浓度对薄膜晶化的影响,并对其结果进行分析讨论。研究结果表明,当衬底温度从200℃逐渐提高到400℃、SiH4浓度从5%降到1%,硅膜的晶化率逐渐提高,结构逐渐由非晶向多晶转变,射频功率对薄膜的晶化状况也有很大影响。     

氢气稀释比例对多晶硅薄膜微观结构和沉积特性的影响

利用电感耦合等离子体增强化学气相沉积法(ICP-PECVD)直接在普通玻璃衬底上低温沉积多晶硅薄 膜,主要研究了不同氢气稀释比例对薄膜沉积特性和微观结构的影响。采用 X 射线衍射仪(XRD)、拉曼光谱仪和 扫描电子显微镜(SEM)表征了在不同氢气比例条件下所制备多晶硅薄膜的微结构、形貌,并对不同条件下样品的 沉积速率进行了分析。实验结果表明：随着混合气体中硅烷比例的增加,薄膜的沉积速率不断增加;晶化率先增 加,后减小;当硅烷含量为4.8%时,晶化率达到最大值67.3%。XRD 和 SEM 结果显示多晶硅薄膜在普通玻璃衬 底上呈柱状生长,且晶粒排列整齐、致密,这种结构可提高载流子的纵向迁移率,有利于制备高效多晶硅薄膜太阳能电池。     

热丝化学气相沉积技术低温制备多晶硅薄膜的结构与光电特性

以金属W和Ta为热丝，采用热丝化学气相沉积 ，在250℃玻璃衬底上沉积多晶硅薄膜.研究了热丝温度、沉积气压、热丝与衬底间距等沉积参数对硅薄膜结构和光电特性的影响，在优化条件下获得晶态比X_c＞90%，暗电导率σ_d=10^-7—10-6Ω ^-1cm^-1，激活能E_a=0.5eV，光能隙E_opt≤1.3 eV的多晶硅薄膜. 关键词： 多晶硅薄膜 热丝化学气相沉积 光电特性     

FTIR法研究BCN薄膜的内应力

采用射频磁控溅射技术,用六角氮化硼和石墨为溅射靶,以氩气(Ar)和氮气(N₂)为工作气体,在Si(100)衬底上制备出硼碳氮(BCN)薄膜。利用傅里叶变换红外光谱(FTIR)考察了不同沉积参数(溅射功率为80～130 W、衬底温度为300～500 ℃、沉积时间为1～4 h)条件下制备的薄膜样品。实验结果表明,所制备薄膜均实现了原子级化合。并且沉积参数对BCN薄膜的生长和内应力有很大影响,适当改变沉积参数能有效释放BCN薄膜的内应力。在固定其他条件只改变一个沉积参数的情况下,得到制备具有较小内应力的硼碳氮薄膜的最佳沉积条件：溅射功率为80 W、衬底温度为400 ℃、沉积时间为2 h。     

氢化硅薄膜介观力学行为及其与微结构内禀关联特性

使用等离子体增强化学气相沉积系统，在射频和直流负偏压的双重激励下制备了本征和掺杂后的氢化硅薄膜.利用拉曼谱对薄膜进行了微结构分析，用纳米压痕系统研究了薄膜的介观力学行为.研究表明：制备于玻璃衬底上的氢化硅薄膜，由于存在非晶态的过渡缓冲层，弹性模量小于相应的制备于单晶硅衬底的薄膜.对于掺杂的氢化硅薄膜，由于磷的掺入使得薄膜晶粒细化、有序度提高，薄膜的晶态比一般在40％以上.而硼的掺入，薄膜晶态比减小，一般低于40％.同时发现，掺磷、本征和掺硼的氢化硅薄膜分别在晶态比为45％，30％和15％左右处，弹性模量较 关键词： 氢化硅薄膜 拉曼谱 弹性模量 晶态比     

磁控共溅射法沉积的硅量子点SiN_x薄膜的光谱特性

采用双极脉冲和射频磁控共溅射沉积法在不同温度的Si(100)衬底和石英衬底上制备了富硅SiNx薄膜。在氮气氛中,于1 050℃下采用快速光热退火热处理,获得了包含硅量子点的SiNx薄膜。采用Fourier变换红外光谱、Raman光谱、掠入射X射线衍射和光致发光光谱对退火后的薄膜样品进行了表征。结果显示:Fourier变换红外光谱中出现了富硅Si—N键,表明薄膜为富硅SiNx薄膜;当衬底温度不低于200℃时,薄膜样品的拉曼光谱中出现了硅纳米晶的Si—Si振动横光学模,掠入射X射线衍射中出现了明显的Si(111)和Si(311)的衍射峰,证实了硅量子点的形成;发现存在一最佳衬底温度(300℃),该条件下获得的硅量子点的数量和晶化率最高;衬底温度为300和400℃的样品的光致发光光谱中均有3个可见荧光峰,结合拉曼光谱结果,用纳米晶硅的量子限域效应和辐射复合缺陷态对荧光峰进行了合理解释;由光致发光光谱计算出的衬底温度为300和400℃的样品的硅量子点平均尺寸分别为3.5和3.4nm。这些结果有助于优化含硅量子点的SiNx薄膜的制备参数,在硅基光电子器件的应用方面有重要意义。     

离子束辅助沉积硅薄膜负极材料的研究

采用离子束辅助沉积法制备了锂离子电池硅薄膜负极材料,研究了硅薄膜的晶体结构、表面形貌和电化学性能.研究结果表明：硅薄膜是非晶态的结构;非晶态硅薄膜发生嵌脱锂反应的电位分别为0.03 V与0.34 V和0.16 V与0.49 V;硅薄膜表现出很高比容量和充放电效率,其可逆比容量和库仑效率分别为3134.4 mAh/g和87.1％;硅薄膜具有优异的循环性能,在0.5C倍率下200次循环后容量保持率为92.2%. 关键词： 硅薄膜 离子束辅助沉积 锂离子电池 负极材料     

集成光学 光波导材料与制备

TN252 2006065160在高阻硅村底上制备低微波损耗的共面波导=Low-mi- crowave loss coplanar waveguides fabricated on high-resis- tivity silicon substrate[刊,英]/杨华(中科院半导体所光电子研究发展中心．北京(100083)),朱洪亮…//半导体学报．—2006．27(1)．—1-4分别在普通的低阻硅衬底、带有3/μm厚氧化硅介质层的低阻硅衬底和高阻硅衬底上设计并制备了微波传输     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

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.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

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.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

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.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Sorting of bending magnets for the SSRF booster

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.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.