铈掺杂氧化铜稀磁半导体材料的光学及磁学特性

发布时间：2018-05-24 05:58

本文选题：CuO:Ce + 光学性质　；参考：《吉林大学》2017年硕士论文

【摘要】：稀土元素具有独特的电子结构,使得稀土元素展现良好的光学及磁学性质。将稀土元素注入到非磁性半导体中有望设计出同时具有磁学、光学及半导体性质的稀磁半导体材料。氧化铜是一种适合作为主体材料的非磁性半导体材料。将铈元素引入氧化铜半导体中,可以使掺杂后的体系同时具有光学与磁学优良的性质和更广的应用前景。本文采用气—雾相化学沉积及随后的热处理方法合成出了氧化铜和铈掺杂氧化铜稀磁半导体材料。通过结构分析表明稀土元素铈作为杂质原子掺入到氧化铜半导体主体结构的晶格中。在氧化铜半导体材料中注入有磁性的稀土离子,杂质离子会占据晶体中出现的晶格空位,进入到晶体中,且分布均匀。研究了未掺杂的氧化铜半导体材料与铈掺杂的氧化铜半导体材料的光学性质。铈掺杂的氧化铜半导体材料的荧光强度明显强于未掺杂的氧化铜半导体材料;铈的掺杂增大了氧化铜半导体材料对可见光吸收的强度及范围;铈掺杂的氧化铜稀磁半导体材料与氧化铜半导体材料的直接带隙分别为1.68 e V和1.75 e V。铈元素的掺杂为氧化铜半导体材料引入了杂质能级,减小了氧化铜半导体材料的带隙。研究了铈掺杂氧化铜半导体稀磁半导体材料的磁学性质,表现出室温铁磁性,其磁性大小是0.04 emu/g;铈掺杂氧化铜稀磁半导体材料的磁性主要来源于铈原子4f电子的间接交换作用。运用第一性原理对三种不同的结构模型进行了结构优化及自旋态密度的计算,理论计算出了氧空位的存在与铈元素的掺杂均对铈掺杂氧化铜稀磁半导体材料提供了磁矩。铈原子f轨道所产生的1.099μB的磁矩是铈掺杂氧化铜稀磁半导体材料磁性的主要来源。
[Abstract]:Rare earth elements exhibit excellent optical and magnetic properties due to their unique electronic structure. It is promising to design dilute magnetic semiconductors with magnetic, optical and semiconductor properties by injecting rare earth elements into nonmagnetic semiconductors. Copper oxide is a kind of nonmagnetic semiconductor material suitable for the main material. The addition of cerium into copper oxide semiconductor can make the doped system have excellent optical and magnetic properties and wider application prospect. In this paper, copper oxide and cerium doped copper oxide diluted magnetic semiconductors were synthesized by gas-fog chemical deposition and subsequent heat treatment. The structure analysis shows that the rare earth element cerium is doped into the lattice of copper oxide semiconductor as an impurity atom. Magnetic rare earth ions are implanted into copper oxide semiconductors and impurity ions occupy the lattice vacancies in the crystals and are distributed uniformly. The optical properties of undoped copper oxide semiconductors and cerium doped copper oxide semiconductors were investigated. The fluorescence intensity of cerium doped copper oxide semiconductors is stronger than that of undoped copper oxide semiconductors, and cerium doping increases the intensity and range of visible light absorption of copper oxide semiconductors. The direct band gap of cerium doped copper oxide diluted magnetic semiconductor and copper oxide semiconductor is 1.68 EV and 1.75 EV, respectively. The doping of cerium introduces the impurity energy level into the copper oxide semiconductor material and reduces the band gap of the copper oxide semiconductor material. The magnetic properties of cerium doped copper oxide thin magnetic semiconductors have been studied. The magnetic properties of cerium doped copper oxide thin magnetic semiconductors show room temperature ferromagnetism, whose magnetic size is 0.04 emu / g. The magnetic properties of cerium doped copper oxide thin magnetic semiconductors are mainly derived from the indirect exchange of cerium atom 4f electrons. The structure optimization and spin state density calculation of three different structure models are carried out by first principle. It is theoretically calculated that the existence of oxygen vacancy and the doping of cerium provide magnetic moment for cerium doped copper oxide diluted magnetic semiconductor material. The magnetic moment of 1.099 渭 B produced by the f orbital of cerium atom is the main source of magnetic properties of cerium doped copper oxide diluted magnetic semiconductors.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN304

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