使用红外干涉仪测量红外材料折射率

使用自行研制的泰曼型红外干涉仪测量红外材料的折射率.在干涉仪的测试臂中加一个旋转台,将被测件放在旋转台上旋转,在旋转过程中经过被测件的光程发生改变,导致干涉条纹发生移动,通过测量条纹的移动数和被测件的旋转角度来计算出被测件的折射率.测量结果显示,25°C时在10.6μm波段处锗单晶的折射率为4.003,硫系玻璃锗砷硒(GeAsSe)的折射率为2.494.折射率测量的误差在10-3量级,增加被测件的厚度会进一步提高折射率的测量准确度,待测红外材料的折射率越低,测量准确度越高.     

红外光学材料折射率温度系数测量装置

本文介绍一台红外光学材料折射率温度系数测量装置。该装置是由温控系统、精密测角系统、光学系统和电器控制系统等组成的一台高精度全自动化测量系统，采用改进的自准直法测量折射率温度系数值。该装置达到的主要技术指标：工作波长为2～12μm，温度范围为-50～150℃，测量不确定度为3%，可满足各种红外光学材料折射率温度系数测量的要求。利用该装置对红外材料锗折射率温度系数值进行了测量，并对测量数据进行了报道。     

使用红外干涉仪测量红外材料折射率

使用自行研制的泰曼型红外干涉仪测量红外材料的折射率.在干涉仪的测试臂中加一个旋转台,将被测件放在旋转台上旋转,在旋转过程中经过被测件的光程发生改变,导致干涉条纹发生移动,通过测量条纹的移动数和被测件的旋转角度来计算出被测件的折射率.测量结果显示,25 °C时在10.6 μm波段处锗单晶的折射率为4.003,硫系玻璃锗砷硒（GeAsSe）的折射率为2.494.折射率测量的误差在10－3量级,增加被测件的厚度会进一步提高折射率的测量准确度,待测红外材料的折射率越低,测量准确度越高.     

红外光学薄膜材料光学常量计算和在宽带增透膜中的应用

使用经典洛伦兹谐振子模型对热蒸发制备的锗、硫化锌以及低吸收稀土氟化物薄膜的红外透射光谱进行拟合,得出这些材料在中长波红外区的光学常量.使用这三种材料设计并制备了锗窗口7.7~15μm宽带增透膜系,通过优化设计并且使用长波红外区吸收小的低折射率材料,在长波区(13~15μm)的透过率测量值有明显提高,15μm处的透过率为89.9％.     

掺氧化硼应力棒的杂质含量研究

用红外吸收法测量了熊猫光纤掺氧化硼应力棒的ＯＨ根含量，用Ｘ射线光电子能谱（ＸＰＳ）仪测量硼、硅、氧和氮的含量，用扫描电子显微镜测量锗分布、芯／包界面的阴极射线发光（ＣＬ）等。对ＯＨ根基波与谐波吸收差别进行了理论分析。 关键词：     

锗在吸收边附近的压力—折射率系数

目前半导体锗在吸收边附近(1550 nm)的压力-折射率系数在实验和理论上并未研究清楚.本文通过测量在不同压力下镀在光纤端面的高结晶度锗薄膜的反射率,来计算得到锗在吸收边附近的压力-折射率系数.本文的实验结果显示,锗在吸收边附近出现反常色散现象,即折射率随能量变化呈正相关,并且其压力-折射率系数出现反常,为正值,这是由于多晶结构中的激子吸收所引起.通过引入描述激子色散的临界点模型,得到锗在吸收边附近的反常色散范围和压力-折射率系数呈正值的范围.本文的结果将有助于基于锗薄膜的通信C波段光学器件的研究.     

新型硅基IV族合金材料生长及光电器件研究进展(特邀)

硅基IV族锗锡和锗铅合金材料带隙随组分可调,并可转变成直接带隙半导体材料,是研制硅基红外探测和发光器件的理想材料。本文首先介绍锗锡和锗铅材料外延生长工作,然后对锗锡光电器件的研究进展进行回顾和讨论。其中,随着锗锡合金中锡组分增加,锗锡光电探测器往高响应度和长探测截止波长方向发展;锗锡激光器的研究则集中在降低激射阈值、提高激射温度和电泵浦方面。本文还对锗铅材料和光电器件的研究进展进行简要介绍和展望。随着硅基高效光源和探测器研究的不断深入,IV族合金材料在硅基红外光电集成领域将继续展现重要的应用价值。     

硅基锗薄膜的红外吸收谱和电学特性

为了解退火对硅基锗薄膜的质量、红外吸收、透射率和电学性质的影响,采用分子束外延方法用两步法在硅基上生长锗薄膜。将生长后的样品分成两部分,其中一部分进行了退火处理。对退火前后的样品用高分辨X射线双晶衍射仪测量了(400)晶面的X射线双晶衍射摇摆曲线,用傅里叶红外光谱仪测量了红外透射率和吸收谱,并用霍尔效应仪测量了退火前后样品的载流子浓度、迁移率、电阻率、电导率和霍尔系数。结果表明,退火后的薄膜质量明显提高。退火后大部分区域吸收增大,透射率明显减小,615~3 730 cm-1区间的透射率均比退火前降低了20%以上。退火后的体载流子浓度增大到退火前的23.26倍,迁移率增大到退火前的27.82倍。     

硅、锗中氧的低温红外吸收

在6—300K下,利用红外傅里叶光谱仪研究了400—4000cm^-1间的硅、锗中氧的红外吸收。采用高分辨条件时,分辨率可达0.5cm^-1。研究了在低温下利用硅的1106cm^-1吸收峰和锗的855cm^-1吸收峰探测硅和锗氧含量的探测限和误差。若样品厚度为2cm,估计在20K下,硅中氧含量探测限～9.6×10¹⁴氧原子·cm^-3,锗中氧含量探测限～3.0×10¹⁴氧原子·cm^-3。同时,对不同生长条件下直拉锗单晶的氧含量进行了研究,并与用锂沉淀法所求得的锗中氧含量加以比较。对不同氧含量的硅样品的1106cm^-1吸收峰在6—300K的变化进行了观察和讨论。 关键词：     

锗/多孔硅和锗/氧化硅薄膜光致发光的比较研究

采用磁控溅射技术,以锗为溅射靶,在多孔硅上沉积锗薄膜,沉积时间分别为4,8和12 min,及以锗-二氧化硅复合靶为溅射靶,在n型硅衬底上沉积了含纳米锗颗粒的氧化硅薄膜,锗与总靶的面积比分别为5%,15%,30%.各样品在氮气氛中分别经过300,600及900℃退火30 min.对锗/多孔硅和锗/氧化硅薄膜进行了光致发光谱的对比研究,用红外吸收谱分析了锗/多孔硅的薄膜结构.实验结果显示,锗/多孔硅薄膜的发光峰位于517 nm附近,沉积时间对发光峰的强度有显著影响,锗层越厚峰强越弱.锗/氧化硅薄膜的发光峰位于580 nm附近,锗与总靶的面积比对发光峰的强度影响较大,锗/氧化硅薄膜中的锗含量越高峰强越弱.不同的退火温度对样品的发光峰强及峰位均没有明显影响.可以认为锗/多孔硅的发光峰是由多孔硅与孔间隙中的锗纳米晶粒两者界面的锗相关缺陷引起的,而锗/氧化硅的发光峰来自于二氧化硅的发光中心.     

Measurement of Refractive Index for High Reflectance Materials with Terahertz Time Domain Reflection Spectroscopy

A method to measure the refractive index for high reflectance materials in the terahertz range with terahertz time domain reflection spectroscopy is proposed. In this method, the THz waveforms reflected by a silicon wafer and high reflectance sample are measured respectively. The refractive index of the silicon wafer, measured with the THz time domain transmission spectroscopy, is used as a reference in the THz time domain reflective spectroscopy. Therefore, the complex refractive index of the sample can be obtained by resorting to the known reflective index of the silicon and the Fresnel law. To improve the accuracy of the phase shift, the Kramers-Kronig transform is adopted. This method is also verified by the index of the silicon in THz reflection spectroscopy. The bulk metal plates have been taken as the sample, and the experimentally obtained metallic refractive indexes are compared with the simple Drude model.     

Giant room-temperature piezoresistance in a metal-silicon hybrid structure

Metal-semiconductor hybrids are artificially created structures presenting novel properties not exhibited by either of the component materials alone. Here we present a giant piezoresistance effect in a hybrid formed from silicon and aluminum. The maximum piezoresistive gage factor of 843, measured at room temperature, compares with a gage factor of -93 measured in the bulk homogeneous silicon. This piezoresistance boost is not due to the silicon-aluminum interface, but results from a stress induced anisotropy in the silicon conductivity that acts to switch current away from the highly conductive aluminum for uniaxial tensile strains. Its magnitude is shown, via the calculation of hybrid resistivity weighting functions, to depend only on the geometrical arrangement of the component parts of the hybrid.     

Spin-dependent photoconductivity in n-type and p-type amorphous silicon

It is found that, as in crystalline silicon, the photoconductivity in amorphous silicon prepared by glow discharge is strongly spin-dependent. In this material, the position of the Fermi level can be smoothly varied by phosphorous or boron doping and the magnitude of the spin-dependent recombination has been measured as a function of the doping: it is found to have a large maximum when the material is intrinsic. The similarities with the spin-dependent effects in crystalline and dislocation silicon suggest that the recombination process in amorphous silicon is the same as in the crystalline material and that dislocation-like centres are responsible for the spin-dependent recombination properties in both materials.     

Thermal diffusivity of light-emitting diode packaging material determined by photoacoustic piezoelectric technique

Thermal property is one of the most important properties of light-emitting diode (LED).Thermal property of LED packaging material determines the heat dissipations of the phosphor and the chip surface,accordingly having an influence on the light-emitting efficiency and the life-span of the device.In this paper,photoacoustic piezoelectric (PAPE) technique has been employed to investigate the thermal properties of polyvinyl alcohol (PVA) and silicon dioxide,which are the new and the traditional packaging materials in white LED,respectively.Firstly,the theory of PAPE technique has been developed for two-layer model in order to investigate soft materials;secondly,the experimental system has been set up and adjusted by measuring the reference sample;thirdly,the thermal diffusivities of PVA and silicon dioxide are measured and analysed.The experimental results show that PVA has a higher thermal diffusivity than silicon dioxide and is a better packaging material in the sense of thermal diffusivity for white LED.     

纳米填充硅橡胶超声干耦合特性*

针对工业超声无损检测领域干耦合材料种类匮乏,且声能透射率低的问题,论文在室温硫化硅橡胶基底材料中添加不同成份和配比的纳米颗粒,制备了不同种类的干耦合材料,给出了干耦合条件下超声波的传输模型,得到了声学传输规律,对比分析了干耦合材料种类、厚度、硬度、超声中心频率及载荷因素对声能传输特性的影响。搭建了声学特性测试实验平台,分别对添加氧化铝、铁和二氧化硅纳米颗粒制备的干耦合材料进行了测定,试验结果表明填充二氧化硅质量分数为5%时,所形成的纳米填充硅橡胶的声阻抗提高了13.5%,使用200kPa预载荷对试块测量时回波幅值提高了18.0%,具有良好的声耦合性能。可为实际超声检测时干耦合材料的制备及应用提供参考。     

低维纳米材料热电性能测试方法研究

通过近几十年的研究,人们对于块体及薄膜材料的热电性能已经有了较全面的认识,热电优值ZT的提高取得了飞速的进展,比如碲化铋相关材料、硒化亚铜相关材料、硒化锡相关材料的最大ZT值都突破了2.但是,这些体材料的热电优值距离大规模实用仍然有较大的差距.通过理论计算得知,当块体热电材料被制作成低维纳米结构材料时,比如二维纳米薄膜、一维纳米线,热电性能会得到显著的改善,具有微纳米结构材料的热电性能研究引起了科研人员的极大兴趣.当块体硅被制作成硅纳米线时,热电优值改善了将近100倍.然而,微纳米材料的热电参数测量极具挑战,因为块体材料的热电参数测量方法和测试平台已经不再适用于低维材料,需要开发出新的测量方法和测试平台用来研究低维材料的热导率、电导率和塞贝克系数.本文综述了几种用于精确测量微纳米材料热电参数的微机电结构,包括双悬空岛、单悬空岛、悬空四探针结构,详细介绍了每一种微机电结构的制备方法、测量原理以及对微纳米材料热电性能测试表征的实例.     

Study of surface treatment processes for improvement in the wettability of silicon-based materials used in high aspect ratio through-via copper electroplating

We report the improvements in wetting characteristics of silicon-based materials with copper electrolyte by various surface treatments to achieve uniform and void free copper deposition in high aspect ratio through-via electroplating. The contact angles of samples such as native silicon, thermally oxidized silicon, silicon nitride, deep reactive ion etched silicon etc, with copper electrolyte, were measured before and after the surface treatments. The wetting of copper electrolyte with silicon nitride coated silicon samples was found to be more than that with thermally oxidized samples. Due to its better wettability, silicon nitride was later used as an insulating layer instead of commonly used silicon oxide in the electroplating experiments. After the SC1 wet surface treatment, the contact angles of all the samples were found to be significantly lower, thus making the surface more suitable for electroplating applications. X-ray photoelectron spectroscopy results verified the presence of polar functional groups on the samples surface, which has helped to improve wetting with copper electrolyte. The conclusions drawn by the experimental results were employed in the high aspect ratio through-via copper electroplating; and void free copper interconnects, having aspect ratio as high as 20, were fabricated.     

Amorphous-to-amorphous phase transition in zeolites

A transition between two amorphous phases with different densities has been detected in zeolites at high pressures using Raman scattering. The Raman spectra measured at amorphous-to-amorphous phase transitions in zeolites and silicon are almost identical; this fact suggests a common nature of these transitions in both single-and multicomponent materials.     

Modeling of optical spectroscopy for the crystalline silicon

The paper is aimed at modeling optical spectra of silicon. Optical spectra of silicon are described with the Logistic function. A satisfactory agreement between the measured and the modeled optical spectra are obtained. The minimum magnitude of the correlation coefficient between experiment and theoretical results is 0.994, and the maximum average relative error is 4.21%. Meanwhile, it is found that the band gap of semiconductor may be determined by fitting absorption coefficient as a function of wavelength. Lastly, the mathematical relationships between the parameters, which are used to link the reflectance of silicon and wavelength, and radiation fluency, are obtained. Consequently, the change of reflectance for silicon can be predicted by both wavelength and dose radiation fluency only one function. All results in this paper are of interest from both optics and materials point of view.     

非晶硅太阳能电池背电极断载热象无损检测

本文介绍了断载热象无损检测的技术,该技术已被证明可用于探测被测物件的结构性质,并能分辨指出缺陷的位置,可以进行定量分析。在工业无损检测应用中具有一定的实用价值。