影响量子阱激光器热特性的主要因素

本文从理论上剖析影响半导体激光器热特性的主要因素,包括:(1)俄歇复合几率的大小;(2)有源区的载流子泄漏;(3)价带间光吸收;(4)激光器有源区材料的禁带宽度Eg.并分析了这四个因素与器件的材料和结构的关系.     

量子阱半导体激光器材料的MBE生长研究

本文阐述了分子束外延（ ＭＢＥ） 技术的特点以及在实现大面积均匀的超薄外延层生长中的应用。利用进口ＭＢＥ 设备, 实现了单量子阱（ＳＱＷ） 和多量子阱（ ＭＱＷ） 半导体激光器外延片的生长, 并对外延片的电学和光学特性进行了测试和分析。     

量子阱效应及其光电性质的表面光电压谱表征

讨论了量子阱限制效应、激子的束缚能以及激子峰的形成,分析了量子阱的光电特性及量子阱表面光电压的形成和特点。结果表明:量子阱有根本不同于体材料的光电特性。     

量子阱效应及其光电性质的表面光电压谱表征

讨论了量子阱限制效应、激子的束缚能以及激子峰的形成，分析了量子阱的光电特性及量子阱表面光电压的形成和特点。结果表明：量子阱有根本不同于体材料的光电特性。     

InGaAs/GaAs应变量子阱能带结构的计算

为了进一步优化半导体激光器的性能,讨论了影响激光器中许多参数的能带结构.以InGaAs/GaAs应变量子阱材料为例,利用有限差分法对考虑价带混合效应的6×6 Luttinger-Kohn哈密顿量精确求解,得到导带和价带的能带结构图.计算结果表明,应变改变了传统无应变量子阱激光器中轻的导带有效质量与非常重的价带有效质量之间的巨大不对称性,更有利于提高激光器的性能.     

多抛物量子阱的共振隧穿

通过求解薛定谔方程得到多抛物量子阱的变换矩阵和透射系数．利用这一结果计算透射系数可以达到任意高的精度．最后讨论了抛物阱的个数对共振隧穿的影响     

浅施主杂质在对称GaAs/AlxGa1-xAs双量子阱中的束缚能

为了研究双量子阱的垒宽、阱宽以及杂质位置对浅施主杂质束缚能的影响,在有效质量近似下,采用变分方法计算了对称GaAs/Alxga1-xAs双量子阱中浅施主杂质的束缚能,本文结果与已有结果吻合较好．体系束缚能随垒宽的增加越来越接近单阱的情况,并且在阱宽较窄时体系束缚能有一最小值．     

分别限制量子阱激光器的载流子限制特性及漏电流

本文在数值求解分别限制量子阶激光器的光增益及阈值电流密度的基础上，计算和分析了漂移和扩散两种机制引起的漏电流对半导体激光器阅值电流密度的影响讨论了激光器的结构参数与漏电流的关系。计算结果和实验值进行了比较。     

磁场作用下抛物量子阱线中激子的束缚能

采用差分的方法在准一维有效势模型下对抛物型量子阱线中激子性质受到磁场的影响进行了计算,分析了磁场对量子阱线中激子的束缚能以及电子和空穴之间的平均距离作用.结果表明:外加磁场会增加量子阱线中激子的束缚能,并且磁场对束缚能的作用会受到量子约束势的影响,在量子约束势较弱时磁场的影响较大,量子约束势较强时磁场的影响较小;外加磁场会减小电子和空穴间的平均距离.     

Laser-field-induced magnon amplification in a magnetic semiconductor quantum well under an external magnetic field

The laser-field induced magnon amplification in a magnetic semiconductor quantum well under an external magnetic field was discussed, it is shown that when the laser frequency is near to the electron cyclotron frequency, no matter how weaker the laser field is, the magnon amplification always occurs. In case of fixed laser frequency, the optical absorption of magnons obeys the definite selection rule to the laser field strength. The rate of change of magnon occupation is calculated, and the amplification condition is given.     

磁场中双量子位Heisenberg模型的纠缠与量子相变

以双量子位Heisenberg模型为例,讨论了磁场方向对纠缠的影响。结果表明：一定温度下,保持磁场的大小不变,仅改变其方向,不仅能获得最大纠缠,还产生了量子相变。     

Characteristics of InGaN multiple quantum well blue-violet laser diodes

Studies on InGaN multiple quantum well blue-violet laser diodes have been reported. Laser structures with long-period multiple quantum wells were grown by metal-organic chemical vapor deposition. Triple-axis X-ray diffraction (TAXRD) measurements show that the multiple quantum wells were high quality. Ridge waveguide laser diodes were fabricated with cleaved facet mirrors. The laser diodes lase at room temperature under a pulsed current. A threshold current density of 3.3 kA/cm2 and a characteristic temperature T0 of 145 K were observed for the laser diode.     

自组装耦合量子点中的类氢杂质

在有效质量近似下,采用有限差分的方法研究了自组装耦合量子点中类氢杂质的结合能随量子点结构参数（量子点尺寸和量子点间距）和杂质位置的变化规律,并计算了外加磁场对此规律的影响。结果表明：杂质结合能随着结构的变化呈现出复杂的变化趋势;杂质位于其中一个量子点的中心位置时,体系的结合能最强;外加磁场将提高杂质的结合能,但量子点结构和杂质位置不同其影响也不同。     

Laser tuned field emission of the carbon nanotube arrays grown on an optical fiber

Laser was coupled into an optical fiber,on which covered a layer of well-aligned carbon nanotubes(CNTs)serving as cathode,to tune the field emission of the cathode.CNT arrays as field emission cathode were synthesized by chemical vapor deposition(CVD)on a naked fiber core.When the laser was coupled into the fiber,the turn-on voltage(Vto at a current density of 1 mA cm?2)decreased from 1.0 to 0.9 kV and the emission current density increased from 0.83 mA cm?2(at a 1 kV bias voltage)to3.04 mA cm?2 on 40μm diameter fiber.A photon absorption mechanism is attributed to the field emission improvement.The estimated effective work function of CNT arrays on the optical fiber decrease from 4.89 to 4.29 eV.The results show the possibility of constructing a waveguide type laser modulated field emission cathode.     

氩在超短脉冲强激光场中电离电子剩余能的研究

利用带有抛物面反射电镜的无磁场TOF（Time-Of-Flight)电子能谱仪，以氩气作为工作介质，测量了不同功率密度、不同气压、不同偏振条件下氩的电子能说，结果表明激光脉冲能量（峰值光强）增强则相应的电子能谱的幅值会有所增强，且会出现新的电子峰，即有新的机制参与电离，充气气压较高时产生下许多低气压时所没有的高能电子，而低能电子峰增强幅度不大，圆偏振光相对于线偏振光有利于高能电子的产生。     

Phase field modeling for dendritic morphology transition and micro-segregation in multi-component alloys

By using the phase field model for the solidification of multi-component alloys and coupling with real thermodynamic data, the dendritic morphology transition and the dendritic micro-segregation of Ni-Al-Nb ternary alloys are simulated in two cases, i.e., varying the alloy composition at a fixed under-cooling and varying the undercooling at a fixed alloy composition. The simulated results indicate that with the increase of the dimensionless undercooling U (U=ΔT/ΔT0, where ΔT is the undercooling and ΔT0 the temperature interval between the solidus and liquidus), the dendritic morphology transfers from dendritic to globular growth in both cases. As to the dendritic micro-segregation, both cases present a regularity of increasing at first and then decreasing.     

Energy spectrum of an electron confined in the hexagon-shaped quantum well

Considering the hexagonal-shaped quantum-scale formations on the surface of thin semiconductor films, a methodology was developed to obtain the analytical solution of the Schrdinger equation when impenetrable walls of a quantum well are treated as mirrors. The results obtained allowed the calculation of the space probability distributions and the energy spectrum of the particle confined in a hex-agonal-shaped well.     

激光再制造过程熔池温度场的数值模拟

建立简化二维非稳态温度场数值模型，采用有限元方法及ANSYS软件求解温度场分布，模拟了一个平板试验件激光再制造过程，其计算结果与文献提供数据比较误差较小，可以采用此计算方法提供的初始温度值和非接触测量温度变化量来控制工艺参数．     

电场效应与光敏树脂中纤维取向的研究

将光敏树脂代替热固化树脂作为结合剂,利用快速成型原理可以实现砂轮的快速制造.为提高超薄型砂轮的机械性能,以超细玻璃纤维作为光敏树脂结合剂的增强材料.本文研究了纤维在电场作用下的取向及其影响因素,探讨了纤维不同的取向对纤维树脂混合物机械性能的影响.