Mn掺杂ZnO光学特性的第一性原理计算

采用基于密度泛函理论(DFT)的第一性原理平面波超软赝势方法计算了纤锌矿ZnO及不同量Mn 掺杂ZnO 晶体的电子结构,分析了掺杂对ZnO 晶体的能带结构、电子态密度、差分电荷分布的影响. 计算结果表明,随着Mn 掺杂含量的增加,ZnO 禁带宽度相应增加并且对紫外吸收区的光吸收能力也随之增强. 关键词： 密度泛函理论(DFT) 第一性原理 超软赝势 Mn掺杂ZnO     

Gax In1-xP缓冲层组分对InP自组装形貌影响的研究

应用缓冲层对自组装结构的作用能Er和自组装结构表面能E8 的协同作用分析了InP自组装结构在GaxIn1-xP缓冲层表面的形貌变化.计算发现缓冲层组分影响自组装结构的形貌.随着缓冲层与InP自组装结构之间应力的增加,InP岛倾向于拉长.理论计算还发现随着自组装结构体积的增大,自组装结构也随之拉长.而且缓冲层的参数决定了自组装结构最小能量状态时的体积大小.应用金属有机物化学气相沉积技术在GaAs衬底上生长了不同的InP/GaInP体系,并对实验得到的自组装体系形貌进行了分析.实验结果证实了以上的理论分析.     

一个实用的生产用Ⅲ-V族化合物半导体材料Turbo-DiscMOCVD生长模型(英文)

在MOCVD质量控制生长模式下 ,通过分析Ⅲ -V族化合物半导体材料在衬底表面的反应过程 ,建立了一个实用的生长模型。此模型是基于分子动力学、化学反应热力学理论分析之上的。针对Turbo -Disc反应体系 ,分析了Turbo -Disc的传热以及质量传送模式后 ,建立了Turbo -Disc的生长模型。在此模型中建立了输入反应室的参数 (IPs)和边界层的生长参数的关系。在对组分匹配的GaInP/GaAs三组分生长体系进行分析时 ,发现此模型是非常有效的 ,理论计算的结果与实验得到的结果非常吻合。应用此模型在实际生产中可以迅速地得到匹配的多组分外延层。     

Improved light extraction of GaN-based light-emitting diodes with surface-textured indium tin oxide electrodes by nickel nanoparticle mask dry-etching

GaN-based light-emitting diodes (LEDs) with surface-textured indium tin oxide (ITO) as a transparent current spreading layer were fabricated.The ITO surface was textured by inductively coupled plasma (ICP) etching technology using a monolayer of nickel (Ni) nanoparticles as the etching mask.The luminance intensity of ITO surface-textured GaN-based LEDs was enhanced by about 34% compared to that of conventional LED without textured ITO layer.In addition,the fabricated ITO surface-textured GaN-based LEDs would present a quite good performance in electrical characteristics.The results indicate that the scattering of photons emitted in the active layer was greatly enhanced via the textured ITO surface,and the ITO surface-textured technique could have a potential application in improving photoelectric characteristics for manufacturing GaN-based LEDs of higher brightness.     

Efficiency enhancement of an InGaN light-emitting diode with a p-AIGaN/GaN superlattice last quantum barrier

In this study, the efficiency droop of an InGaN light-emitting diode （LED） is reduced slgnlncanUy oy using a p-AlGaN/GaN superlattice last quantum barrier. The reduction in efficiency droop is mainly caused by the decrease of electron current leakage and the increase of hole injection efficiency, which is revealed by investigating the light currents, internal quantum efficiencies, energy band diagrams, carrier concentrations, carrier current densities, and radiative recombination efficiencies of three LED structures with the advanced physical model of semiconductor device （APSYS）.     

纤锌矿型量子级联激光器的界面与受限声子比较

利用传输矩阵方法对纤锌矿型量子级联激光器有源区的界面与受限声子进行了研究.计算结果显示:在纵光学频域有一组界面声子与二组受限声子存在,而且最低频率的两个界面声子在一定条件下能转变为受限模式.通过比较界面声子与受限声子的色散及声子势发现两者有很大不同,且计算电声散射速率可以发现由这两种声子引起的散射率是可比拟的.     

Comparison of nitride-based dual-wavelength lightemitting diodes with an InAIN electron-blocking layer and with p-type doped barriers

The advantages of nitride-based dual-wavelength light-emitting diodes （LEDs） with an InA1N electron blocking layer （EBL） are studied. The emission spectra, carrier concentration in the quantum wells （QWs）, energy band and internal quantum efficiency （IQE） are investigated. The simulation results indicate that an LED with an InA1N EBL performs better over a conventional LED with an A1GaN EBL and an LED with p-type-doped QW barriers. All of the advantages are due to the enhancement of carrier confinement and the lower electron leakage current. The simulation results also show that the efficiency droop is markedly improved and the luminous intensity is greatly enhanced when an InAlN EBL is used.     

Si掺杂对AlGaInP/GaInP多量子阱性能的影响

采用LP-MOCVD技术在n-GaAs衬底上生长了AlGaInP／GaInP多量子阱红光LED外延片。以X射线双晶衍射技术和光致发光技术对外延片进行了表征,研究了Si掺杂对AlGaInP／GaInP多量子阱性能的影响。研究表明：掺Si能大大提高(Al0．3Ga0.7)0.5In0.5P／Ga0.5In0.5P多量子阱的发光强度。相对于未故意掺杂的样品,多量子阱垒层掺Si使多量子阱的发光强度提高了13倍,阱层和垒层均掺Si使多量子阱的发光强度提高了28倍。外延片的X射线双晶衍射测试表明,Si掺杂并没有使多量子阱的界面质量变差。     

掺杂与Al组分对AlGaInP四元系LED发光效率的影响

通过分析载流子在发光二极管(LED)双异质结中的输运情况,得到了在不同的P型掺杂程度下,限制层Al组分与LED发光效率的关系,从而可以探索P型掺杂与Al组分对发光效率影响的规律,得到的结论对于LED的器件结构设计以及MOCVD材料生长有一定的指导意义.     

用于动物细胞和组织培养的新型LED生物光源系列

采用透镜组扩大光束、透镜阵列聚焦和点阵光曲面聚集光能三种光路设计,通过选择各光源中的四个工作参数调节光源输出的辐射照度,本文研制出可用于动物细胞和组织培养使用的、不同强度的三种新型LED生物光源,并使用统计分析软件SPSS拟合得出它们的辐射照度经验计算公式.