【作者】 蒋婧思；

【导师】 候延冰；

【作者基本信息】 北京交通大学 ， 光学， 2008， 硕士

【摘要】 稀磁半导体学是自旋电子学的一个重要分支。稀磁半导体是将磁性过渡金属或稀土离子掺入传统非磁性半导体并占据其晶格位置,通过磁性离子与非磁性离子之间的sp-d或RKKY交换作用使半导体的微观磁矩在特定外界条件下具有一定取向性,并从宏观上表现出磁性。稀磁半导体将同时利用载流子的电荷和自旋态两个自由度,从而使得高密度半导体集成电路、非易失性存储器等器件的实现成为可能。在稀磁半导体的多种基质材料中,氧化锌由于其具有独特的光电特性及广泛的潜在应用背景,成为近年来稀磁半导体研究中的热点之一。为寻找一种方便高效的稀磁半导体制备方法,本文分别利用磁控溅射和溶胶-凝胶法制备了铁离子掺杂氧化锌基稀磁材料,并对所制备材料的磁学和相关物理特性进行了研究。本文通过靶材局域掺杂的方式来实现磁控溅射法中铁离子的掺杂,制备了多种不同铁元素掺杂浓度的氧化锌薄膜。使用电感耦合等离子光谱仪ICP测量了薄膜中铁离子的实际掺杂浓度,并通过X射线衍射对薄膜制备条件及高温退火对薄膜结晶状态的影响进行了研究。研究结果表明通过该方法制得了具有良好结晶状态的氧化锌薄膜。使用超导量子干涉仪对不同制备条件下的薄膜进行了磁滞回测量。溶胶-凝胶法与磁控溅射技术相比具有易于控制掺杂量的特点。本文利用该方法和高温烧结相结合分别制备Zn_1-xFe_xO稀磁半导体粉末和薄膜,讨论了掺杂浓度对材料物理特性的影响,并对不同形态材料的晶格结构、表面形貌进行了比较分析。分别测量了粉末和薄膜样品的磁化率随温度变化曲线以及磁滞回曲线。通过对实验结果进行比较分析,发现磁控溅射和溶胶-凝胶法所制备的样品在结构和晶格取向上呈现出较大差异,使用溶胶凝胶法所得到的Zn_1-xFe_xD样品与磁控溅射法相比,光谱有明显展宽。磁控溅射法所制备的薄膜样品中没有观察到磁滞回线,而溶胶-凝胶法所制备的粉末和薄膜两种不同形态的样品在低温条件下均观察到了明显的磁滞现象。更多还原

【Abstract】 As a branch of Spintronics, diluted magnetic semiconductor （DMS）is to combine magnetic irons into traditional semiconductors and to replace the lattice position of the semiconductor. The sp-d or RKKY interaction between magnetic irons and current carrier of the original non-magnetic semiconductor irons can cause the uniformed spin orientation, and thus the material will have ferromagnetic performance in macroscopic. DMS takes advantage of both charge and spin properties of electrons, and will play an important role in the integrated circuit and other material with memory. ZnO is a kind of widely used material with excellent performance in both optics and electronics, this made it extremely popular in the research o f DMS.ZnO with Fe as the doping material has been fabricated in two different ways of magnetron sputtering and Sol-Gel, in order to achieve a method for convenient synthesize of the DMS. Target space doping has been used in the method of magnetron sputtering to achieve the doping of Fe iron, and Zn_1-xFe_xO film has been synthesized in different conditions. The density of Fe iron was measured with Inductively Coupled Plasma （ICP）. Lattice structure of the film has been tested by X-ray Diffraction and the result shows that ZnO film with fine crystal structure can be synthesized by this method. Magnetic properties of the film were also tested with Superconductivity Quantum Interference Device （SQUID）.Sol-Gel is a kind of chemical method, comparing with magnetron sputtering it has the advantage of low-costing and easy to control the amount of doping. Both powder and film samples have been synthesized with this method, fluorescence spectrum and lattice structure were tested, magnetic loop and the M-T curve of the fabricated sample were measured with SQUID.The result shows that there are obvious differences in the nature of the samples fabricated with magnetron sputtering and Sol-Gel. No magnetic loop has been found in samples fabricated with magnetron sputtering method, but there is obvious magnetic loop in both powder and film samples fabricated with Sol-Gel in the temperature of 10K.更多还原