一种多孔硅生物免疫传感器的研究

对多孔硅样品进行热氧化和硅烷化处理,通过共价结合的方法将HYSA生物抗体固定到多孔硅的孔洞中;测量了加入BSA发生抗原抗体反应前后的荧光光谱和反射谱.实验结果表明加入生物分子后多孔硅发光峰消失,抗原抗体反应后发光强度增强,反射谱红移.该项研究为开发免标记的多孔硅光学生物免疫传感器奠定了基础.     

一种基于多孔硅光子器件的免标记生物检测法

本文提出了一种免标记、快速便捷、低成本、较 高灵敏度的生物检测的新方法, 其检测原理是通过测量多孔硅中因生物反应引起的折射率的变化来实现对生物分子的检测。 文中采用单层多孔硅样品作为传感器基底,将包虫病(EgP38)抗原链接到多孔硅中,再在 样品上滴加不同浓度的EgP38抗体分子,抗原与抗体发生特异性反应后,采用椭圆偏振仪检 测样品折射率的变化量,通过分析传感器中因发生生物反应而导致的折射率变化量,从而实 现生物检测。该方法首次采用椭圆偏振法实现了对包虫病生物分子的检测,对抗体分子的检 测限为142 nM。     

掺杂浓度对BaF2:PbWO4闪烁晶体发光性能的影响

用多坩埚温度梯度系统生长了一批不同掺杂浓度的BaF2:PbWO4晶体,研究了这些晶体的透过光谱、x-射线激发光谱(XEL)与晶体掺杂浓度的关系,结果发现合适浓度的掺杂增加了晶体的透过率、XEL光谱强度,并使XEL光谱峰红移.当掺杂浓度1000mol-ppm浓度时,晶体的透过率明显增大、XEL光谱强度明显增强.当掺杂浓度...     

硅基光子晶体热释电红外传感器衬底的研制

在借助光刻等微电子工艺手段的基础上,通过控制交替变换的阳极氧化电流成功地制备出了阵列化的多孔硅一维光子晶体,然后在其表面沉积了一层500 nm Si3N4用于改善其表面粗糙度,使该结构更好地应用于热释电红外传感器之中。通过傅里叶红外反射谱(FTIR)测试证明该样品有较好的光学反射性能,探索了将这种阵列化的多孔硅一维光子晶体应用于制备高性能红外热释电传感器衬底的可行性。     

多孔阳极氧化铝薄膜的结构和特性

采用阳极氧化法,制备了二维有序多孔氧化铝薄膜.用金相显微镜观察了一次阳极氧化和二次阳极氧化后多孔氧化铝的表面形貌.用X射线衍射仪、扫描电子显微镜和UV-VIS-NIR光谱仪等测试手段对多孔氧化铝薄膜进行了表征.结果表明,多孔氧化铝薄膜是非晶态结构,多孔氧化铝薄膜具有整流特性.多孔氧化铝的光学反射率随入射波长红移呈增加趋势,反射光谱具有明显的干涉现象.     

光激发半导体硅片对宽带太赫兹波的调制研究

利用光泵浦-太赫兹(THz)探测(OPTP)技术,研究 了THz波在Si半导体界面间的传输行为。通过改变抽 运光密度从而改变样品表面的载流子浓度,实现对THz波透射/反射的有效调制。在外加中心 波长为800nm 的飞秒激光激发块体半导体Si片时,成功实现了对宽带THz波时域谱包括入射THz 脉冲振幅和 相位以及THz波次级反射峰抗反射的调制。光激发Si片可以获得任意载流子浓度 的Si片实现对 THz脉冲振幅的调制,调制度达到90%以上;光激发Si片能够使THz脉 冲的相位发生负延迟,随着 泵浦光密度的增加,负的相移越来越明显,随着频率的增高,负的相移也越来越明显;光激 发Si片还能够 对THz波的次级反射峰进行调制,随着泵浦光密度的改变,实现对次级反射峰的π相位以及 次级反 射峰抗反射的调制。光激发Si片对宽带THz波时域谱的调制为THz波在通信、国防安全等领域 的应用奠定了基础。     

Ca_2P_xSi_(1-x)能带结构及光学性质的第一性原理计算

采用基于第一性原理的贋势平面波方法,对不同P掺杂浓度正交相Ca2Si的几何结构、能带结构、态密度和光学性质进行计算,比较不同浓度P掺杂的几何结构、电子结构和光学性质。对不同P含量下Ca2PxSi1-x的几何结构比较研究得出:随着P浓度增加Ca2PxSi1-x的晶格常数a、c减小,b增加,体积减小;掺杂浓度对电子结构的影响主要体现在P掺杂Ca2Si使得费米面向导带偏移,且随着掺杂浓度的增加而更深入地嵌入导带中,费米面附近由Ca-d Si-p及P-p电子构成的导带和价带均向低能方向移动,带隙随着掺杂浓度的增大而增大;掺杂浓度对光学性质同样有较大的影响,Ca2PxSi1-x的静态介电函数、折射率随着P掺杂浓度的增加而增加,而反射谱随着P掺杂浓度的增加而减小。适当的P掺杂能够提高Ca2Si对光的吸收系数和折射率,降低光的反射,提高了Ca2Si的光电转换效率。     

铜掺杂多孔硅的光致发光及其载流子的复合过程

采用浸泡镀敷的方法在多孔硅表面形成了一镀铜层,通过对掺铜前后多孔硅的光致发光(PL)谱和傅里叶变换红外(FTIR)吸收光谱的研究,讨论了铜在多孔硅表面的吸附对其光致发光的影响。实验表明,掺铜多孔硅的光致发光谱出现两个发光带,其中能量较低的发光带随主发光带变化,并使多孔硅的发光峰位蓝移。多孔硅发光峰位的蓝移,是由于在发生金属淀积的同时伴随着多孔硅表面Si的氧化过程(纳米Si氧化为SiO2)的缘故。     

多孔硅有效介电函数研究

采用改进过的Maxwell-Garnett模型研究了入射光波长和多孔硅的孔隙率对反射光谱和介电光谱的影响,结果表明:(1)随着入射光波长的增大,多孔硅的反射率先增大后减小,而随着孔隙率的增大反射光谱出现了明显的下塌趋势,且孔隙率越大下塌得越明显;(2)随着孔隙率的增加,多孔硅复介电光谱出现明显的蓝移现象,且多孔硅有效介电常数的实部和虚部均变小.此外还对这种现象给出了较为合理的解释.     

Si基热光可调谐窄带平顶滤波器

利用Si基键合技术、台阶型F-P腔结构以及Si良好的热光效应,研制了一种新型全Si基的热光调谐窄带平顶滤波器.器件的平顶宽度为2nm,3dB带宽为4.4nm,自由谱宽约为8.5nm,在外加电场作用下,共振峰红移3.3nm.     

Porous silicon optical cavity as an immunosensor platform

A novel porous silicon based optical Fabry-Perot cavity structure is prepared as a label-free immunosensor platform for detecting antigen-antibody. The lagurus zona pelluciad 3 (LZP3) and the specificity of the polyclonal anti-LZP3 antibodies are employed in our laboratory as the target and the probe, respectively. Firstly, the antibodies are immobilized to the porous silicon optical cavity using silanization and glutaraldehyde (GA) chemistry. And then, after the antigen-antibody reaction, it is monitored that the red shift of the reflection spectrum of the immunosensor increases with the antigen concentration. This research also plays a potential role for the extensive applications in immunoassay.     

Research on immunosensor based on porous silicon

Porous silicon is functionalized using thermal oxidation and silanization. The HYSA antibodies are immobilized to the porous surface in this paper. The changes in the reflection spectrum and photoluminescence spectrum are investigated when BSA are attached to the PS surface. The result shows that the luminescence peak of PS disappears. After the antigen- antibody reaction, the higher light emission is observed and the reflection spectrum also red shifts. Therefore, this research lays a foundation for the development of sensitive label-free optical immunosensor.     

Porous silicon biosensor for detection of variable domain of heavy-chain of HCAb antibody

In this paper, we produce porous silicon (PSi) by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain of heavy-chain antibody (VHH). The binding of hen egg white lysozyme (HEWL) and VHH causes a red shift in the reflection spectrum of the biosensor. The red shift is proportional to the VHH concentration in the range from 14 μg . ml-1 to 30 μg . ml-1 with a detection limit of 0.648 ng . ml-1. The research is useful for the development of label-free biosensor applied in the rapid and sensitive determination of small molecules.     

Luminescent Colloidal Dispersion of Silicon Quantum Dots from Microwave Plasma Synthesis: Exploring the Photoluminescence Behavior Across the Visible Spectrum

Aiming for a more practical route to highly stable visible photoluminescence (PL) from silicon, a novel approach to produce luminescent silicon nanoparticles (Si‐NPs) is developed. Single crystalline Si‐NPs are synthesized by pyrolysis of silane (SiH₄) in a microwave plasma reactor at very high production rates (0.1–10 g h^?1). The emission wavelength of the Si‐NPs is controlled by etching them in a mixture of hydrofluoric acid and nitric acid. Emission across the entire visible spectrum is obtained by varying the etching time. It is observed that the air oxidation of the etched Si‐NPs profoundly affects their optical properties, and causes their emission to blue‐shift and diminish in intensity with time. Modification of the silicon surface by UV‐induced hydrosilylation also causes a shift in the spectrum. The nature of the shift (red/blue) is dependent on the emission wavelength of the etched Si‐NPs. In addition, the amount of shift depends on the type of organic ligand on the silicon surface and the UV exposure time. The surface modification of Si‐NPs with different alkenes results in highly stable PL and allows their dispersion in a variety of organic solvents. This method of producing macroscopic quantities of Si‐NPs with very high PL stability opens new avenues to applications of silicon quantum dots in optoelectronic and biological fields, and paves the way towards their commercialization.     

A label-free single photonic quantum well biosensor based on porous silicon for DNA detection

The single photonic quantum well (PQW) structures are successfully fabricated on p-type silicon wafer by electrochemical etching process, and are used for DNA detection firstly. The red shift of resonance peak is caused by the changing refractive index of PSi layer, which results from coupling of organic molecules into pores. When the porous silicon (PSi) based single PQW biosensors are immersed in complementary deoxyribonucleic acid (DNA) with different concentrations ranging from 0.625 μM to 10.000 μM, a good linear relationship is observed between the red shift of resonance peak and the complementary DNA concentration. Experimental results show that the detection sensitivity of PSi-based single PQW biosensors is 3.04 nm/μM with a detection limit of 32 nM for 16-base pair DNA oligonucleotides.     

Silicon Nanocrystals in Liquid Media: Optical Properties and Surface Stabilization by Microplasma‐Induced Non‐Equilibrium Liquid Chemistry

Surface engineering of silicon nanocrystals directly in water or ethanol by atmospheric‐pressure dc microplasma is reported. In both liquids, microplasma processing stabilizes the optoelectronic properties of silicon nanocrystals. The microplasma treatment induces non‐equilibrium liquid chemistry that passivates the silicon nanocrystals surface with oxygen‐/organic‐based terminations. In particular, the microplasma treatment in ethanol drastically enhances the silicon nanocrystals photoluminescence intensity and causes a clear red‐shift (≈80 nm) of the photoluminescence maximum. The photoluminescence properties are stable after several days of storage in either ethanol or water. The surface chemistry induced by the microplasma treatment is analyzed and discussed.     

牛奶水溶液荧光光谱影响因素的研究

研究了纯牛奶、高钙奶、高钙低脂奶和过期约10天的纯牛奶水溶液的三维荧光光谱特征。实验结果表明,牛奶水溶液的荧光峰随着激发波长的增长而红移;当激发波长大于340nm时,荧光光谱上出现次级荧光峰,且该峰也随激发波长的增加而红移。通过对比研究发现,牛奶的浓度对牛奶水溶液荧光光谱的影响不大,而牛奶品种对其荧光光谱影响较大,尤其是高钙低脂奶。过期的牛奶水溶液在较长或者较短波长激发光激励下,荧光峰强度高于未过期的同类牛奶。初步分析了在一定激发波长下高钙低脂奶、过期牛奶的荧光强度比其他样品荧光强度强的原因。研究结果可为利用荧光光谱技术检测牛奶品质提供参考。     

自填隙原子对Si晶体性能影响的研究

运用第一性原理的超软赝势方法研究了Si晶体中自填隙形成的多种缺陷对体Si电子结构和光学性质的影响.理论计算表明,缺陷使体 Si 材料的晶格常数、体积、电学和光学性质等产生了不同程度的改变,空位缺陷导致Si晶体材料吸收光谱红移.     

Internally Referenced Remote Sensors for HF and Cl2 Using Reactive Porous Silicon Photonic Crystals

Remote detection of reactive analytes using optical films constructed from electrochemically prepared porous Si‐based photonic crystals is demonstrated. Porous Si samples are prepared to contain either surface oxide or surface Si‐H species, and analyte detection is based on irreversible reactions with HF_(aq) or Cl_2(g) analytes, respectively. HF dissolves silicon oxide from the porous matrix, causing an irreversible blue‐shift in the resonance peak of the photonic crystal. Cl₂ reacts with the native Si‐H species present on the surface of as‐etched porous Si to generate reactive silicon halides that evaporate from the surface and/or react with air to convert to silicon oxide. Either Cl₂‐related process reduces the net refractive index of the material that is detected as a blue shift in the spectrum. With sufficient analyte concentrations or exposure times, the spectral blue shifts are visible to the unaided eye. A portion of the porous nanostructure is filled with inert polystyrene, which acts as an internal spectral reference. The polymer fiducial protects that portion of the sensor from attack by the corrosive analytes. Reflectance spectra from both the polymer‐filled and the unfilled, reactive porous layers are acquired simultaneously. The fiducial marker also allows elimination of artifacts associated with shifts of the resonance peak upon changing the angle of incidence of the optical probe. Theoretical angle‐resolved spectra (transfer matrix method) show a good match with the experimental data. High‐temperature air or room‐temperature ozone oxidation reactions are used to prepare the HF‐reactive surface, and it is found that the ozone oxidation reaction produces a greater sensitivity to HF (LLOD of 0.1% HF in water).