优化生长的In_xGa_(1-x)As缓冲层上双势垒In_yGa_(1-y)As/Al_zGa_(1-z)As/GaAs/Al_zGa_(1-z)As多量子阱应变状态测量

一种多步生长方法应用于GaAs衬底上的In_xGa_(1-x)As缓冲层的MOCVD生长.在这种In_xGa_(1-x)As缓冲层上生长的In_yGa_(1-y)As/Al_zGa_(1-z)As/GaAs/Al_zGa_(1-x)As双垫垒量子阱材料表现出了很好的晶格特性和光学性质.超晶格的室温光伏谱中出现很强的22H高阶机制吸收峰,表明超晶格界面质量很好.主要应用X射线双晶衍射方法,给出了样品中各层的应变状态.据此,合理地解释了样品的光学测试结果

MOCVD生长大功率单量子阱激光器

介绍了MOCVD生长的高质量GaAs和AlAs材料以及(Al)GaAs/AlGaAs分别限制单量子阱激光器.GaAs材料的77K迁移率为122.700cm~2/(V·s),GaAs/AlAs具有均匀陡变的界面.激光器的最大光输出功率为4W,平均光功率密度达4MW/cm~2,斜率效率为1.2W/A,在1W恒功老化4000小时电流增加小于10%,预计寿命可超过两万小时

超晶格结构X射线衍射分析及其结构参数的计算

在经典的X光运动学理论的基础上, 加入一些改进, 不再直接计算超晶格的结构因子Fool, 而是计算各原子面的散射波函数, 获得了卫星峰的模拟峰形和pendellosung条纹, 克服了原来不能解释峰形和pendellosung现象的缺点。还用此方法对GaAlAs／GaAs超晶格和GeSi／Si应变超晶格进行了模拟计算, 与实验吻合很好, 证明了理论的正确性

超晶格中GaAs/InGaAs界面与InGaAs/GaAs界面的特性差异

In_xGa_(1-x)缓冲层上生长In_yGa_(1-y)As/GaAs超晶格(x<y).阱层处于压缩应变,垒层处于伸张应变,其厚度均小于Matthaews-Blakeslee(M-B)平衡理论计算的临界厚度.透射电子显微镜及俄歇电子能谱、二级离子质谱测试发现,GaAs/In_yGa_(1-y)As界面铟组分过渡区比In_yGa_(1-y)As/GaAs界面铟组份过渡区窄;In_yGa_(1-y)As合金阱层中,靠近GaAs/In_yGa_(1-y)As界面一端的铟组分更大.用In_yGa_(1-y)As合金层中铟的分凝理论解释了超晶格中铟组分的分布特征.透射电子显微观察表明,GaAs/In_yGa_(1-y)As界面比In_yGa_(1-y)As/GaAs界面平整.提出一种新的弛豫机制来解释压缩应变和伸张应变的不同,对两个界面特性的差异给予解释

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies