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We report a special phenomenon on switching behaviour and the electroluminescence (EL) spectrum shift of doped diamond thin films. Nitrogen and cerium doped diamond thin tilms were deposited on a silicon substrate by microwave plasma-assisted chemical vapour deposition system and other special teclmiques. An EL device with a three-layer structure of nitrogen doped diamond/cerium doped diamond/Si02 thin films was made. The EL device was driven by a direct-current power supply. Its EL character has been investigated, and a switching behaviour was observed. The EL light emission colour of diamond films changes from yellow (59Onm) to blue (454nm) while the switching behaviour appears. 相似文献
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Electronic structures of PbWO4 crystals containing F-type colour centres with the lattice structure optimized are studied within the framework of the fully relativistic self-consistent Dirac-Slater theory, using a numerically discrete variational (DV-Xα) method. The calculated results show that F and F^+ centres have donor energy levels in the forbidden bands. Their optical transition energies are 1.84 eV and 2.21 eV, respectively, which correspond to the 680nm and 550 nm absorption bands. It is predicted that the 680 nm and 550nm absorption banas originate from the F and F^+ centres in PbWO4 crystals. 相似文献
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利用完全势缀加平面波局域密度泛函近似,计算了含铅空位的PbWO4(PWO)晶体的电子结构,模拟计算了复数折射率、介电函数及吸收光谱的偏振特性.比较含铅空位的PWO晶体与完整的PWO晶体的吸收光谱及其偏振特性,得到与铅空位相关的吸收光谱及其偏振特性,计算结果与实验结果基本相符.计算得到的含铅空位的PWO晶体的光学偏振特性反映了PWO晶体的结构对称性.计算结果表明PWO晶体中350,420,550和680 nm的吸收带的出现与PWO晶体中铅空位的存在直接相关. 相似文献
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本文提出了3He和3H等三重子填充SU(3)群35维不可约表示的可能性.计算了三重子三十五重态的波函数及分支比,给出了多重态内部各三重子态的质量之间的关系,并预言了可能存在的三重子系统. 相似文献
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论量子力学的教学研究张启仁(北京大学技术物理系,北京1ll871)多年来在高等学校教师中流行一种看法:教学是重复性劳动,只有科研才是创造性的。对此,我不敢苟同。姑不论科研工作有大量重复性劳动,没有重复何来创造。就以教学而言,有许多问题要思考、研究、尝... 相似文献
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Electronic structures of PbMoO4 crystals containing F-type colour centres with the lattice structure optimized are studied within the framework of the fully relativistic self-consistent Dirac-Slater theory, using a numerically discrete variational (DV-Xa) method. The calculated results show that F and F+ centres have donor energy levels in the forbidden band. The optical transition energies are 2.166eV and 2.197eV, respectively, corresponding to the 580nm absorption bands in PbMoO4 crystal. The 580nm absorption band in PbMoO4 is originated from the F-type colour centres. 相似文献
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从发现光电效应以来,人们对光与物质的相互作用的研究越来越多,越来越深入。尤其在激光发明以后,光场的强度越来越大,光束的准直性越来越好,人们可以利用它做大量的实验,从而发现了很多新的实验现象,例如阈上电离[1],Kapitza_Dirac效应[2],高阶谐波效应[3]等。这些现象用原有的光电理论已无法解释,从而发展了一些多光子电离的理论,其中以美国SouthernUniversity的郭东升教授及其合作者所发展的非微扰理论较为引人关注。这篇文章将详细介绍郭教授的工作以及相关的实验结果与理论研究的比较,希望人们对多光子领域的研究有更深一步的了解。文章首先介绍光与物质相互作用的理论基础,即Volkov解的得出及其讨论;文章第二部分将对多光子过程进行描述,并用第一部分结果进行一些定性的讨论;第三部分介绍Kapiza_Dirac效应的实验结果与理论研究的比较;第四部分对整个理论体系予以综合评论,以及对强激光和物质作用的理论和实际应用的前景展望。 相似文献
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