Epitaxy of Strain-relaxed SiGe, Ge Films and Fabrication of Ge Photodetectors on Si Substrates

硅基硅锗材料因其优越的性能，特别是与成熟硅微电子工艺相兼容，在硅基光电子器件如光电探测器、场效应晶体管等方面得到了广泛的应用，硅基硅锗薄膜生长及相关器件的研制引起了人们浓厚的兴趣。然而由于锗与硅的晶格失配度较大，在硅基上生长高质量硅锗和锗薄膜仍然是一个挑战性的课题，需要引入缓冲层技术。本论文采用低温缓冲层技术在UHV/CVD系统上生长出高质量硅基硅锗和锗弛豫衬底，并在此基础上研制出硅基长波长锗光电探测器。主要工作和研究成果如下： 为了促进外延层应变弛豫、改善表面形貌，我们提出了低温Ge量子点缓冲层制备SiGe弛豫衬底的技术。分析了低温Ge量子点缓冲层在调节应力、湮灭位错等方面的机理，系统地研...Si-based SiGe materials have been extensively applied in optoelectronic devices such as photodetectors and high mobility metal-oxide-semiconductor field effect transistors due to their advantageous properties, especially in compatibility with Si microelectronic processing. Si-based SiGe materials and their related devices have attracted great attention. However, it is a great challenge to directly...学位：理学博士院系专业：物理与机电工程学院物理学系_凝聚态物理学号：1982006015317

The shape transformation of Si patterned-substrate in thermal decomposition of native oxide during vacuum annealing

利用超高真空化学气相淀积(uHV/CVd)系统,在不同的温度、环境氛围及脱O过程参与等条件下对全息法制备的二维周期图形SI衬底进行退火,通过原子力显微镜(AfM)进行表征与分析,研究真空高温脱O过程对图形衬底表面形态变化的影响。结果表明,真空环境使衬底表面的SI原子可以自由运动,脱O过程增强了SI原子在表面的迁移,温度会影响SI原子的扩散速率,3个因素的共同作用导致图形深度变浅,侧壁坡度变缓。此外,在周期图形台面的边缘,观察到环形有序分布的纳米SI岛。2D-period patterned Si substrate is annealed in ultra-high vacuum chemical vapor deposition(UHV/CVD)under variational conditions including different temperature,environment,thermal decomposition of native silicon oxide.The morphology properties of annealed patterned-substrate are obtained by atomic force microscopy(AFM).The effect of annealing parameters on shape transformation of Si patterned-substrate is studied.The results indicate that the Si atoms can diffuse freely on substrate surface in vacuum and the diffusion is enhanced during thermal decomposition of native oxide.The diffusion velocity is affected by temperature.These effects result in the decrease of the depth of pattern and gradient of side wall.In addition,ordered nanometer Si islands are formed on the mesa of patterned-substrate.国家自然科学基金资助项目(60336010;60676027);国家重点基础研究发展计划“973”资助项目(2007CB613404

无乳链球菌致儿童细菌性脑膜炎抗感染实践

目的分析药师参与的无乳链球菌致儿童细菌性脑膜炎的治疗实例,促进抗感染药物在细菌性脑膜炎的合理使用及探讨全敏感无乳链球菌抗感染治疗不佳情况下的药学思维。方法药师参与无乳链球菌致儿童细菌性脑膜炎病例治疗,对全敏感无乳链球菌抗感染治疗不佳原因进行剖析总结。结果药师对部分抗感染方案给出建议获得采纳后治疗取得进展,针对国内耐药情况对细菌性脑膜炎的经验治疗方案建议采用美罗培南联合万古霉素;对万古霉素进行血药浓度监测并在浓度指导下进行剂量调整;对病原菌明确为全敏感无乳链球菌抗感染治疗出现反复情况下提出细菌耐受可能并给予利奈唑胺联合青霉素抗感染建议。结论药师参与临床治疗有助于治疗方案改进,不生搬硬套并领会指南有助与临床沟通,药师深入了解细菌耐药特性及抗菌药物药动药效学有助于优化用药,纠正用药习惯

Establishment of MDCK cell lines which stably express visualable human neonatal Fc receptor

[目的]建立稳定表达融合EGFP的人新生儿Fc受体（h FcRn）的MDCK细胞株。[方法]构建重组慢病毒质粒p EGFP-h FcRn,采用四质粒包装系统共转染HEK 293T细胞生产重组慢病毒,感染MDCK细胞后对EGFP阳性细胞进行流式单细胞分选;通过Western Blot及EGFP-β2m荧光共定位验证h FcRn的完整性,并用流式细胞仪检测h FcRn与人Ig G的结合活性。[结果]测序结果表明成功构建p EGFP-FcRn慢病毒表达载体;感染后EGFP阳性MDCK细胞比例约为26.5%,流式单细胞分选后得到纯阳性细胞;荧光共定位及Western Blot均检测到h FcRn的完整表达;流式分析表明细胞株上的h FcRn与Ig G存在p H依赖性结合。[结论]成功获得稳定表达具有生物活性的可视化h FcRn的MDCK细胞株。[ Objective] To establish MDCK cell line stably expressing EGFP- human neonatal Fc receptor（hFcRn） fusion protein. [ Methods ] The lentiviral expression vector for EGFP - hFcRn fusion protein was constructed. Generating by co - transfection of four -plasmids into HEK 293T cells ,the lentivirus particles were used to infect MDCK cell line. EGFP positive single cell was obtained by FACS, and then FcRn expression was identified by fluorescence co -location with EGFP - β2m and confirmed by Western Blot. Flow cytometry was used to detect binding activity of hFcRn and human IgG. [ Results ] DNA se- quencing demonstrated that the lentivirus vector pEGFP - FcRn was constructed successfully. The percentage of EGFP - posi- tive ceils was about 26.5% after infection. Expression of the complete protein was detected through fluorescence co - location and Western Blot, respectively. Flow cytometry analysis showed that the cell lines could pH - dependently capture human IgG. [ Conclusion] MDCK cell line stably expressing functional visualable hFcRn was established.基金项目：国家自然科学基金项目（“结构生物学指导的HBV治疗性抗体人源化及其关键技术研究”,No.31600748;“抗呼吸道合胞病毒高中和活性抗体的保护机制研究”,No.81401668;“基于广谱中和单抗的通用型流感疫苗设计及其结构基础研究”,No.31670934

Growth of high quality Ge epitaxial films on Si substrate by low temperature buffer technique

采用低温缓冲层技术,在SI衬底上生长了质量优良的gE薄膜。利用原子力显微镜(AfM)、双晶X射线衍射(Xrd)和拉曼散射等研究了薄膜的晶体质量。结果表明,由于无法抑制三维岛状生长,低温gE缓冲层的表面是起伏的。然而,gE与SI间的压应变几乎完全弛豫。当缓冲层足够厚时,后续高温gE外延层的生长能够使粗糙的表面变得平整。在90 nM低温gE缓冲层上生长的210 nM高温gE外延层,表面粗糙度仅为1.2 nM,位错密度小于5x105CM-2,Xrd的峰形对称,峰值半高宽为460 ArC SEC。High-quality and thick Ge epitaxial films are grown on Si substrates utilizing the low-temperature(LT) buffer technique by ultrahigh vacuum chemical vapor deposition(UHV-CVD) and are characterized by atomic force microscope,X-ray diffraction,and Raman spectroscopy.The results show that the LT Ge buffer is rough due to the three-dimensional islands formations,but the misfit stress is nearly fully relaxed.Fortunately,the rough LT Ge surface is effectively smoothed by subsequent growth at elevated temperature when the LT Ge buffer is thick enough and the compressive strain is largely relaxed.Finally,the 210 nm Ge epitaxial film with smooth surface(root-mean-square roughness of 1.2 nm),low threading dislocation density(5×105 cm-2),and sharp and symmetric X-ray diffraction peak(full width at half maximum of ～460 arc sec) is achieved on LT Ge buffer with thickness of 90 nm.国家重点基础发展研究计划资助项目(2007CB613404

益气化痰方对抑郁模型大鼠行为学的影响

目的:观察比较中药复方益气化痰方不同剂量配比对抑郁模型大鼠行为学的影响。方法:雄性大鼠随机分为正常组、模型组、益气化痰Ⅰ组、益气化痰Ⅱ组,以孤养加慢性轻度不可预见性应激方法建立大鼠抑郁症模型,采用Open-Field法、1%蔗糖水消耗实验及体重变化观察抑郁模型大鼠的行为学变化。结果:与正常组相比,模型组大鼠糖水消耗量明显减低,水平得分、垂直得分、修饰次数和大便颗粒数均明显下降,且体重增长缓慢,有显著性差异(P<0.05);与模型组相比,益气化痰Ⅰ组、益气化痰Ⅱ组均能够不同程度增加糖水消耗量、垂直得分、大便颗粒、修饰次数和体重,较模型组有显著性差异(P<0.05);且益气化痰Ⅰ组改善作用更明显。结论:益气化痰方能有效的改善抑郁模型大鼠的行为学变化;其中补气药作用明显优于化痰药

Fabrication and characteristics of Si-based Ge waveguide photodetectors

以外延gE薄膜为吸收区,在SI基上制备了gE波导光电探测器。利用超高真空化学汽相淀积(uHV/CVd)设备,采取低温高温两步法,在SI(100)衬底上外延出厚度约为500nM的高质量纯gE层。探测器采用脊型波导结构,Al电极分别制作在波导的台面上下形成背对背肖特基结。I-V特性测试表明,在-1V偏压下,暗电流密度为0.2MA/CM2。由于SI与gE热失配引起外延的gE薄膜受到0.2%张应变,减小了gE带隙,光响应波长范围扩展到1.60μM以上。在70MW、1.55μM入射光照射下,测得光电流比暗电流高出近1个数量级。A Si-based Ge waveguide photodetector was fabricated and characterized.High-quality tensile strained Ge layer(about 500nm)was epitaxially grown on a Si(100)substrate by low-and high-temperature two-step growth method in ultrahigh vacuum chemical vapor deposition.Two metal-germanium schottky junctions on and under the waveguide were fabricated to form metal-germanium-metal photodetector and the dark current density of 0.2 mA/cm2 at the bias of-1 V is obtained.The photocurrent response in the wavelength range expands to 1.6 μm due to the 0.2% tensile strain in the Ge layer and the photocurrent is higher in one order magnitude than the dark current at 1.55 μm.国家自然科学基金资助项目(60676027);国家重点基础研究发展计划“973”资助项目(2007CB613404);国家自然科学基金委重点基金资助项目(60837001);福建省重点科技资助项目(2006H0036

基于差分统计方法的舌象纹理特征的分析与识别

为探讨舌诊客观化的方法,依据中医纹理判断的特点,针对舌象纹理特征分析,应用灰度差分统计方法,从对比度(CON) 、角度方向二阶矩(ASM) 、熵(ENT) 、平均值(MEAN) 四个参数,进行舌象纹理的量化和定义分类,并尝试将舌质老嫩的判别方法应用与临床舌质的判别,总体识别率为74 %。上海市教育青年基金资助项目(02CK22

Luminescence of Strain Compensated Si/Si_(0.62)Ge_(0.38) Quantum Well Grown on Si_(0.75)Ge_(0.25) Virtual Substrate

由于SI/SIgE异质结构的带阶差主要发生在价带,为实现高效率的发光,本文从理论上设计了在硅基SI1-XgEX虚衬底上外延应变补偿的SI/S1-ygEy(y>X)量子阱的能带结构,将量子阱对电子的限制势垒提高到100MEV以上。在实验上,采用300℃生长的gE量子点插入层,制备出薄的SIgE驰豫缓冲层(虚衬底),表面gE组份达到0.25,表面粗糙度小于2nM,驰豫度接近100%。在我们制备的SIgE缓冲层上外延了应变补偿SIgE/SI多量子阱结构,并初步研究了其发光特性。In this paper,band structures of strain compensated Si/S_(1-y)Ge_y(y>x) quantum well grown on Si_(1-x)Ge_x virtual substrate was design to enlarge the conduction band offset up to 100meV for improving luminescence.The fully strain-relaxed Si_(0.75)Ge_(0.25) virtual substrate was prepared by inserting a low-temperature Ge islands layer in ultra-high vacuum chemical deposition.The root-mean-square surface roughness of the virtual substrate is less than 2nm.The luminescence of the strain compensated Si/SiGe quantum well on the virtual substrate was investigated.国家重点基础研究发展计划资助项目2007CB613400;国家自然科学基金资助项目(60676027;50672079

Assessing ecological risks of different valence states of Cr to marine organisms by species sensitivity distributions

应用生态风险评价中的物种敏感性分布(SSd)方法构建了3种不同形态(Cr、Cr3+、Cr6+)的重金属Cr对海洋生物的SSd曲线。在此基础上计算了3种形态的Cr对不同海洋生物的5%危害浓度(HC5)和其不同暴露浓度对海洋生物的潜在影响比例(PAf),比较了海洋脊椎动物和无脊椎动物对不同形态的重金属Cr的敏感性以及不同形态的Cr的急性生态风险,并且评价了两个港湾海水水体中常见形态的重金属Cr的联合生态风险。结果表明,3种形态的重金属Cr的HC5的大小顺序为Cr3+>Cr6+>Cr。浓度小于10μg/l时,Cr、Cr3+、Cr6+三者生态风险差异不大,且都处于相对较低的水平。在10μg/l的暴露浓度下,三者所影响的海洋生物比例均未超过5%。随着浓度升高,生态风险也相应增大。当浓度达到1 000μg/l时,分别有23.43%,13.73%和17.27%的物种受到Cr、Cr3+、Cr6+的损害,此时三者的生态风险差异也比低浓度时有所增大。当不同形态的重金属Cr浓度在不同的范围时,不同生物的敏感性大小顺序会发生变化。三种形态的重金属对无脊椎动物的生态风险均比脊椎动物(本文即指鱼类)大。两个海湾水体重金属生态风险的大小顺序为宁德海域(0.66%)>福清海域(0.63%)。Species sensitivity distributions(SSD) method was used to assess the ecological risk of three valence states of Cr(Cr,Cr3+,Cr6+) to marine organisms.The acute toxicity data(LC50 or EC50) were collected from ECOTOX database and SSD curves were fitted based on BurrIII and ReWeibull function.The acute ecological risks of different valence states of Cr and the sensitivity of different marine species(vertebrate and invertebrate) to these different valence states of Cr were compared by the hazardous concentrations for 5% of the species(HC5) and the potential affected fractions(PAF).Then the HC5 values of these different valence states of Cr were in the order:Cr3+> Cr6+> Cr.When exposure concentration was lower than 10 μg/L,no significant differences among the ecological risks of Cr,Cr3+ and Cr6+ was observed.Also,none of these four observations exceeded the threshold of 5%(PAF) at the exposure level of 10 μg/L.The ecological risks of the heavy metals increased as the exposure concentration increased.When came up to 1 000 μg/L,23.43%,13.73% and 17.27% of marine species would be affected by Cr,Cr3+ and Cr6+,respectively.The order of sensitivity to marine species varied with different concentration of heavy metals.The ecological risk of all these three valence states of Cr to invertebrate was higher than to fishes.The case studies showed that the ecological risk of different valence states of Cr in the Seas of Ningde was higher than that in the Seas of Fuqing.国家自然科学基金资助项目(31101902); 国家海洋局青年海洋科学基金资助项目(2011143); 海洋公益性行业科研专项经费资助(201105015); 福建省自然科学基金资助项目(2012J05074); 国家海洋局第三海洋研究所基本科研业务费专项资金资助项目(海三科2011006