宽输出电压的半导体激光器驱动电源研究

介绍了一种大功率、宽输出电压范围的半导体激光器脉冲驱动电源的设计方法。根据半导体激光器脉冲驱动电源高电压、大电流的工作特性需求,脉冲放电环节采用多模块级联与功率开关管线性控制脉冲放电相结合的拓扑结构,这样既实现了脉冲电流平滑稳定,又提高了输出电压等级与功率。充电环节采取LCC谐振变换器结构,其抗负载短路和开路的能力非常适用于脉冲放电场合。该脉冲电源输出参数为:电压0~1000 V,电流1~160 A,脉宽200~250 μs,频率100 Hz内可调,具备较宽泛灵活的输出范围,可适应不同规模的激光二极管阵列。最后,分别通过单模块、两模块与三模块小功率级联型驱动实验验证了采用多模块级联与功率开关管线性控制脉冲放电相结合方法的可行性。     

人工欧泊填充InP后的形貌和反射谱特性

制备了人工opal晶体模板,运用MOCVD方法在SiO2人工opal球体间填充了高折射率的InP晶体,选择了MOCVD生长InP的有关参数.样品扫描电子显微镜及反射谱结果检测显示,InP晶体在二氧化硅间隙中的生长是均匀的,具有较好的结晶质量;高介电常数的InP的填充使人工欧泊光子晶体的光子禁带效应增强,反射峰移向长波长区.光学特性检测结果与理论计算值得到较好的符合.     

Blue InGaN light-emitting diodes with dip-shaped quantum wells

InGaN based light-emitting diodes (LEDs) with dip-shaped quantum wells and conventional rectangular quantum wells are numerically investigated by using the APSYS simulation software. It is found that the structure with dip-shaped quantum wells shows improved light output power, lower current leakage and less efficiency droop. Based on numerical simulation and analysis, these improvements on the electrical and the optical characteristics are attributed mainly to the alleviation of the electrostatic field in dip-shaped InGaN/GaN multiple quantum wells (MQWs).     

双波长InGaN/GaN多量子阱发光二极管的光电特性

为了实现高显色指数和流明效率的白光发光二极管,在(0001)蓝宝石衬底上利用金属有机化学气相沉积系统,生长了双波长发射的InGaN/GaN多量子阱发光二极管结构.通过对不同In组分含量的双波长发射发光二极管结构的光致发光和电致发光性能进行分析,结果表明In组分含量对双波长发射发光二极管的光致发光谱的稳定性及发光效率有重...     

双波长InGaN/GaN多量子阱发光二极管的光电特性

为了实现高显色指数和流明效率的白光发光二极管,在（0001）蓝宝石衬底上利用金属有机化学气相沉积系统,生长了双波长发射的InGaN/GaN多量子阱发光二极管结构.通过对不同In组分含量的双波长发射发光二极管结构的光致发光和电致发光性能进行分析,结果表明In组分含量对双波长发射发光二极管的光致发光谱的稳定性及发光效率有重要影响.此外,用双蓝光发射的芯片来激发YAG:Ce荧光粉实现了高显色指数白光发射.     

Doping transition metal ions as a method for enhancement of ablation rate in femtosecond laser irradiation of silicate glass

We present a doping method to improve the femtosecond laser ablation rate and promote ablation selectivity. Doping transition metal ions, Co2＋ or Cu2＋, in silicate glass apparently change absorption spectroscopy and induce resonant absorption at wavelengths of 600 and 800 nm, respectively. Comparing with femtosecond laser processing of the same glass without doping, we find that the threshold fiuenee decreases and the ablation rate increases in resonant absorption in doped silicate glass. Resonant absorption effectively increases multiphoton ionization for seed-free electron generation, which in turn enhances avalanche ionization.     

Simulation study of blue InGaN multiple quantum well light-emitting diodes with different hole injection layers

InGaN-based light-emitting diodes with p-GaN and p-AlGaN hole injection layers are numerically studied using the APSYS simulation software.The simulation results indicate that light-emitting diodes with p-AlGaN hole injection layers show superior optical and electrical performance,such as an increase in light output power,a reduction in current leakage and alleviation of efficiency droop.These improvements can be attributed to the p-AlGaN serving as hole injection layers,which can alleviate the band bending induced by the polarization field,thereby improving both the hole injection efficiency and the electron blocking efficiency.     

Y对Fe-Si-B 合金非晶形成能力及软磁性能的影响

本文通过铜模吸铸法和单辊甩带法分别制备出一系列楔形试样和非晶条带试样, 系统研究了稀土金属Y对Fe₇₈Si₉B₁₃合金非晶形成能力及其软磁性能的影响. 结果表明, 少量Y取代 Fe-Si-B 非晶合金中的Fe 可大大提高该合金的非晶形成能力并促进过冷液相区的产生. 当Y含量为3 at.%时, 合金具有最大的非晶形成能力, 其临界厚度为313 μm, 相应的非晶过冷液相区宽度达到65 K. 该系列非晶合金具有优良的软磁性能, 其矫顽力(H_c)均低于200 A/m, Y含量为1 at.%时, 饱和磁感应强度(B_s) 达到最大值1.67 T.     

Be1-xMgxO合金的能带特性与相结构稳定性研究

采用基于密度泛函理论的平面波赝势方法,对纤锌矿和岩盐矿结构Be_1-xMg_xO合金的晶格常数、能带特性和形成能进行计算,分析了不同Mg组分下不同结构的Be_1-xMg_xO合金晶格常数和能带差异.结果表明:随着Mg组分的增大,纤锌矿和岩盐矿Be_1-xMg_xO合金的晶格常数都线性增加,但它们的能隙都逐渐减小.对于相同Mg组分的Be_1-xMg_xO合金,岩盐矿结构的能隙要大于纤锌矿结构.当Mg组分为0.89时,Be_1-xMg_xO合金由纤锌矿相转变为岩盐矿相.为了使理论值与实验值相一致,对Be_1-xMg_xO合金的能隙计算值进行修正,得到纤锌矿和岩盐矿Be_1-xMg_xO合金的能隙弯曲系数b值分别为3.451 eV和4.96 eV.对纤锌矿BeO-MgO-ZnO三元合金的能隙和弯曲系数与晶格常数关系做了分析.     

3,3′-偶氮-(6-氨基-1,2,4,5-四嗪)的合成与表征

以硝酸胍和水合肼为原料,经7步反应合成了高氮含能化合物3,3′-偶氮-(6-氨基-1,2,4,5-四嗪),其结构经1H NMR,13C NMR,IR及元素分析表征。