过渡族和稀土族元素掺杂GaN基稀磁半导体性能比较

Properties Comparison of Transition Elements and Rare-Earth Elements Doped GaN Based Diluted Magnetic Semiconductor

实验中采用离子注入结合快速退火工艺,在MOCVD外延生长的n型GaN薄膜表面分别注入Mn、Cr、Gd、Sm离子,得到了厚度约200nm的稀磁半导体薄膜,并用XRD、RBS、SQUID对三种样品的微结构和磁性能进行了测试分析。结果表明,稀土族元素Gd、Sm掺杂的GaN样品在掺杂浓度远低于过渡族Mn、Cr掺杂样品的情况下,仍能得到相同量级的饱和磁化强度,计算得到的Gd、Sm离子有效磁矩近似甚至大于其原子本征磁矩,而Mn、Cr的离子有效磁矩远小于其原子本征磁矩,说明在过渡族和稀土族元素掺杂的GaN基稀磁半导体中,有着两种完全不同的磁耦合机制。

Combined ion implantation with RTA process in experiments,Mn,Cr,Gd,Sm ions were implanted on the n-type GaN film surface Epi-grown by MOCVD,respectively,200 nm diluted magnetic semiconductor thin films were got,and the micro-structure of three samples were analyzed by XRD,RBS,SQUID,and the magnetic properties were tested.The results show that under the condition of doping concentration of Gd,Sm-doped GaN samples much lower than that of transition Mn,Cr-doped samples,the same order of magnitude of saturation magnetization can still be received.The calculated ion effective magnetic moment of Gd,Sm is similar or even greater than its atom intrinsic magnetic moment.And Mn,Cr ion effective atomic magnetic moment is much smaller than its intrinsic magnetic moment.It reveals that two different types of magnetic coupling mechanisms exist in the transition group elements and rare earth-doped GaN-based diluted magnetic semiconductor.