新型III族氮化物基室温铁磁性单晶薄膜材料研究

项目名称： 新型III族氮化物基室温铁磁性单晶薄膜材料研究

项目编号： No.60876004

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 刘超

作者单位： 中国科学院半导体研究所

项目金额： 36万元

中文摘要： GaN基稀磁半导体材料是近年来在自旋电子学领域中受到广泛关注的研究热点和最有希望获得室温以上铁磁性的稀磁半导体材料，有希望将磁、光、电特性集成于一体、研制出具有速度快、功耗低、集成度高和非易失性等特点的新型自旋电子器件，在量子计算、量子通讯等现代信息技术领域中有十分重要的应用前景。本项目以室温铁磁性的GaN基DMS材料制备工艺及其物性表征为研究方向，在蓝宝石衬底上用MOCVD外延生长GaN、AlN、AlGaN和InGaN薄膜的基础上，采用双能态离子注入技术制备了Sm、Eu、Tb、Dy、Er、Yb等稀土元素和Cr单一或两种元素共掺杂的III族氮化物基DMS系列样品，获得了多种类型室温铁磁性的III族氮化物基DMS材料样品。深入研究了高温退火因素对DMS样品表面形貌、微结构、磁学、电学和光学性能的影响，提出了GaN基DMS材料铁磁性机理的新观点。实验上首次发现了GaN：Tb样品的室温亚稳态铁磁性现象和证实了GaN：Sm样品中Sm3+离子的巨磁矩现象。上述成果为优选稀土元素掺杂的GaN基系列DMS材料制备工艺奠定了科学基础，并为进一步探索和揭示其铁磁性机理提供了实验依据，具有重要的学术意义。

中文关键词： 稀磁半导体;氮化镓;离子注入;铁磁性薄膜

英文摘要： GaN-based diluted magnetic semiconductors (DMS) is a widely concerned research focus in the field of Spintronics in recent years and the most promising candidate materials which could obtain ferromagnetism above room temperature. It is expected to integrate magnetic, optical and electrical properties together to develop novel spintronic devices with fast speed, low energy consumption, high integration and non-volatility, which could provide attractive prospect for modern information technology such as quantum computation and quantum communication. In this project, we focused on the preparation techniques of RT ferromagnetic GaN-based DMS and the characterization of its physical properties. On the basis of MOCVD-grown GaN, AlN, AlGaN and InGaN thin films that were deposited on sapphire substrates, we prepared III-Nitride based DMS samples doped with rare-earth elements such as Sm, Eu, Tb, Dy, Er and Yb by double energy ion implantation technique as well as samples co-doped with Cr and the above mentioned rare-earth elements，and acquired multiple types of room-temperature ferromagnetic III-Nitride-based DMS materials. We have studied the effects of high-temperature annealing on the surface morphology, microstructure, magnetic, electrical and optical properties of the samples, and proposed new viewpoints of the ferromagnetic mechanism of the GaN-based DMS materials. For the first time, we observed room-temperature metastable ferromagnetism in GaN:Tb samples and confirmed the colossal magnetic moment of Sm3+ ions in GaN:Sm samples experimentally. The above mentioned achievements have significant academic importance. They have not only laid the foundation of optimal selection of GaN-based rare-earth doped DMS materials, but also provided experimental data for exploring and revealing the ferromagnetic mechanism.

英文关键词： Diluted magnetic semiconductors; GaN; Ion implantation; Ferromagnetism