1/f噪声功率谱的加权最小二乘法拟合

本文导出了用最小二乘法对1/f噪声功率谱进行曲线拟合的具体算法,提出了一种提高拟合精度的加权法,并与传统方法对比分析了拟合误差,用实际处理结果证明了加权法对1/f噪声功率谱低频部分的拟合质量有很大改善,能提高曲线拟合的整体效果.     

共掺铝的掺铒光纤放大器的光谱特性

用Stark能级分裂的变化分析了掺铝改变掺铒光纤放大器(EDFA)光谱特性的原理，并用改进型化学气相沉积法(MCVD)结合溶液浸泡掺杂法制作了采用不同掺铝比例的掺铒光纤，测试了用这几种光纤制作的放大器的自发辐射谱，得出掺铝浓度的提高使荧光谱的峰值往短波长移动，与Stark能级分裂理论分析得到的结果相一致。同时采用截断法测试了两种不同掺铝浓度的掺铒光纤的吸收谱，实验结果表明掺铒光纤中增加铝的含量将提高铒离子浓度，并提高掺铒光纤的吸收系数，减短掺铒光纤放大器中的掺铒光纤长度。高掺铝掺铒光纤放大器具有更宽更平坦的增益谱线，可以适用长距离波分复用(WDM)系统。     

土壤中微量重金属元素Pb的激光诱导击穿谱

从实验上测定了土壤在可见光谱区的激光诱导击穿光谱(LIBS),对测定的光谱结构进行了分析,并对可观测的谱线进行了归属,得出土壤所含的主要元素和部分微量元素;测定了不同Pb掺杂浓度下土壤中微量元素Pb405.78 nm谱线的强度,采用内标法拟合得到了该分析谱线的激光诱导击穿光谱定标曲线,由定标曲线的拟合结果计算得到Pb元素的检测限质量分数为36.7×10-6。     

多孔硅的椭偏光谱研究

本文用椭偏光谱法研究多孔硅．采用有效介质理论，从椭偏光谱数据定出不同实验条件下制备成的多孔硅样品的孔隙率．其次，从紫外一可见范围的椭偏光谱得到多孔硅介电函数虚部谱，并与单晶硅相应谱作比较．结果表明主峰带隙随着多孔硅空隙率增加而向高能方向移动，同时在＜３ｅＶ区出现新的吸收带，与能带理论计算结果相符．     

多步旋涂CsPbBr3薄膜复光学常数的椭偏光谱研究

为了研究多步旋涂法制备的CsPbBr₃薄膜的光学常数，以溴化铅和溴化铯为原料，采用多步旋涂法在硅和FTO衬底上制得CsPbBr₃薄膜。利用光弹调制式椭偏光谱仪对硅衬底上的薄膜进行了椭偏光谱分析，使用Tanguy和Tauc-Lorentz 3组合模型对变角度的椭偏光谱进行参数拟合，得到了薄膜光学常数在1.00 eV～5.00 eV范围内的色散关系，并利用荧光发射光谱、吸收谱验证椭偏拟合结果。结果表明，多步旋涂法制备的CsPbBr₃薄膜的光学常数与其它方法相比具有一定的差异性，其中折射率可能与薄膜表面粗糙度呈负相关；椭偏拟合所得带隙为2.3 eV,验证了荧光光谱、吸收谱的计算结果。该研究为多步旋涂法制备的CsPbBr₃薄膜椭偏光谱拟合分析提供了参考。     

光纤中的多级斯托克斯及反斯托克斯谱线

本文叙述在多模光纤中产生的多级受激拉曼散射谱，作了两种不同掺杂的SiO2光纤中的受激拉曼散射谱。对掺锗硅光纤得到16级斯托克斯线及10级反斯托克斯线。对掺磁硅光纤获得了13级斯托克斯线及4～5级斯托克斯线。测出了各级谱线的峰值波长及相对强度分布，并作了简单讨论。     

掺铒光纤放大器光谱特性和噪声特性的研究

报道了利用 980nm波长的单抽运光源抽运掺铒光纤得到的放大自发辐射谱 (ASE谱 )特性 ,对在较小抽运功率条件下得到的掺铒光纤荧光谱特征图进行了探讨 ;在此基础上对采用两个980nmLD作抽运光源的掺铒光纤放大器 (EDFA)的噪声特性进行了实验研究 ,得到具有良好噪声特性的结果     

GaAs异质面太阳电池光谱响应和暗J-V特性的拟合分析

本文用LPE法制备了GsAs异质面太阳电池,测量了电池的光谱响应(SR)和暗J—V特性,推导了它们的理论公式,用这些理论公式对测量值进行了曲线拟合。从SR拟合求得三个区的少子扩散长度、AlGaAs层厚度、结深、前表面和界面复合速度等七个结构参数。从暗∫—V特性拟合求得扩散电流密度分量、复合电流密度分量、结品质因子和串并联电阻等五个电学参数。最后分析拟合结果,讨论了这些参数对电池效率的影响,提出提高效率的方法。     

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。     

用激光诱导击穿光谱技术定量分析矿石样品中Si和Mg

激光诱导击穿光谱(LIBS)技术被用来定量分析矿石样品元素成分.波长为1064 nm的Nd:YAG脉冲激光聚焦在样品表面后产生激光等离子体,等离子体原子发射谱由微型光谱仪记录.为了优化实验条件,研究了激光能量和延时时间等部分参数对谱线强度的影响.实验发现激光脉冲能量对光谱信号的影响大.在选定的变化范围内,改变延时对光谱的影响较小.实验中分别以硅(Si I谱线251.6 nm)和镁(Mg I谱线285.2 nm)为分析线,采用外定标法对硅和镁的含量进行了反演,测得的硅和镁元素含量值与标准值的相对误差分别为7%和3%.     

半导体单晶材料的表面光伏效应

本文报导了测量半导体单晶材料(Si、GaAs、GaP、InP)的表面光伏谱和少子扩散长度,以及用微型计算机进行曲线拟合计算出材料的掺杂浓度、载流子迁移率、表面势垒宽度和表面势垒边界的界面复合速度等参数;得到的掺杂浓度与霍尔方法的测量值做了对比;本文还讨论了曲线拟合计算结果的可靠性和准确性.     

Materials for light emitting diodes

III–V semiconductor display diodes fall into three material categories: direct, indirect, and diode-phosphor combinations. The light generation mechanisms are well understood in each case. On the basis of the luminous efficacy achieved in the laboratory, the merit of the various materials is in the order: GaP: N (green), GaP: Zn, O (red), GaInP (yellow), GaAsP (red), GaAlAs (red) and GaAs-phosphor combinations (red, green, blue). A more comprehensive assessment of quality must take into account factors such as the economic feasibility of the methods of synthesis, the applicability to monolithic arrays, and the suitability of spectra (hue, contrast, saturation, etc.). The degree of importance of these matters and the limitations of the various materials are less well-defined at present. New developments which may have an impact on the future of display diodes include the use of Al_xGa_1-xP in place of GaP to shift spectra to shorter wavelengths, the possible development of very bright direct alloys of InP with either GaP or A1P, and the doping of GaAsP with N to extend its range of colors.     

Modelling of electroluminescent GaP diodes I (V) and L (V) characteristics

An investigation of the diode characteristics has been under taken in order to identify the physical mechanisms governing its behaviour at different bias levels. The influence of the various physical and technological parameters upon the electrical and optical behaviour of the component have been illustrated.A complete theoretical simulation of a GaP diode is presented and the principal results are examined. An analytical model of the devices operation, based on the physical analysis of the behaviour of the GaP diodes at all bias levels, is given. A method for determining the parameters (lifetimes) which govern the operation of the diode is described, followed by the presentation of the experimental results obtained from various GaP diodes.     

Potentials of GaP as millimeter wave IMPATT diode with reference to Si, GaAs and GaN

This paper presents the simulation results of DC,small-signal and noise properties of GaP based Double Drift Region( DDR) Impact Avalanche Transit Time( IMPATT) diodes. In simulation study we have considered the flat DDR structures of IMPATT diode based on GaP,GaAs,Si and GaN( wurtzite,wz) material. The diodes are designed to operate at the millimeter window frequencies of 94 GHz and 220 GHz. The simulation results of these diodes reveal GaP is a promising material for IMPATT applications based on DDR structure with high break down voltage( V_B) as compared to Si and GaAs IMPATTs. It is also encouraging to worth note GaP base IMPATT diode shows a better output power density of 4. 9 × 10~9 W/m~2 as compared to Si and GaAs based IMPATT diode. But IMPATT diode based on GaN( wz) displays large values of break down voltage,efficiency and power density as compared to Si,GaAs and GaP IMPATTs.     

基于Multisim和Excel的二极管特性仿真实验

在二极管的特性教学中,同时引入了Multisim和Excel软件。检索中国期刊网中发现,没有相同研究方法和成果出现,应用Multisim对二极管的特性进行测试仿真,应用Excel对测试结果进行伏安特性和电阻特性的曲线拟合、显示,相比传统的实物电路测试更加方便和快捷,相比传统的手绘特性曲线更加精确、直观。在教学实践中,引导学生对仿真数据和特性拟合曲线进行分析,对二极管特性有更清晰和全面的认识。     

Junction-temperature estimation in AlGaInP light-emitting diodes using the luminescence spectra method

This study proposes a practical method to estimate the junction temperature of AlGaInP LEDs using the luminescence spectra method. The peak wavelength shift of LEDs is due to the energy band gap shrinking. The temperature dependence of the bandgap of AlGaInP LEDs is derived from those of the underlying binary compounds AlP, GaP, and InP. Based on this, a theoretical model for the dependence of the peak wavelength on junction temperature is developed. Experimental results on the junction temperature of AlGaInP red light-emitting diodes are presented. Excellent agreement between the theoretical and experimental temperature dependence of the peak wavelength is found.     

Ultra-wide electroluminescence spectrum of LED heterostructures based on GaPAsN semiconductor alloys

In this paper, we present the results of the white light-emitting diodes (LEDs) construction based on GaPAsN semiconductor alloys on a GaP substrate. Heterostructure electroluminescence with a continuous emission spectrum in the range from 350 nm to 1050 nm is observed. The output of light through the side walls and the face side of the sample enabled us to achieve white light emission by means of ultra-wide electroluminescence spectrum covering all visible spectrum and part of the near IR spectral range. While extracting emission through substrate, the short-wavelength part of the visible spectra is absorbed at GaP layer.     

高激发功率对GaP∶N发光谱的影响

讨论了掺氮磷化镓（GaP∶N）荧光光谱的峰值强度（孤立氮等电子中心束缚激子发光峰A、最邻近N-N对束缚激子发光峰NN1和次邻近N-N对束缚激子发光峰NN3）随激发强度的变化规律,并在发光跃迁动力学方程中计入了由于高激发密度引起的样品温度升高,而导致孤立氮A的能级NA和最邻近N-N对NN1的能级的热激发的增强,得到了R（即最近邻N-N对(NN1)束缚激子发光峰与孤立N等电子中心束缚激子发光峰的强度比INN1/IA）与掺N浓度和激发光强的变化关系。利用实验数据进行拟合,得到了更好的拟合结果,并讨论了用此法计算GaP∶N样品中氮浓度时应注意的一些问题。     

多声子尖峰叠加在连续钟形谱带上的发光光谱

<正> 虽然有几个作者已经研究了GaP:(Bi),AlxGa1-xP:(Bi)的发光光谱,但涉及光谱的谱形和谱线展宽的本质等问题还没引起注意和得到讨论。本文介绍这两个材料的光谱研究结果,并就上述问题展开讨论。     

Ideal GaP surface-barrier diodes

The properties of GaP diodes with metal?semiconductor (m.s.) potential barriers are described. The structure was manufactured by the chemical deposition of metal (gold or metal) on the n GaP surface. The properties of these m.s. structures (forward current/voltage and photocurrent/photon-energy characteristics and typical parameters) are extremely close to an ideal theoretical model. Comparison of properties of the m.s. structures with properties of the best GaP structure made by vacuum evaporation shows that the method of chemical deposition which is more simple permitted she manufacture of more perfect m.s. structures.