退火温度对GaN：Mn薄膜微结构、电学及磁学性能的影响

Effects of Annealing Temperature on Microstructure, Electronic and Magnetic Properties of GaN:Mn films

通过Mn离子注入非故意掺杂GaN外延层制备了GaN:Mn薄膜,研究了退火温度对其微结构、电学和磁学性能的影响。结果表明:所有样品均呈现为单晶纤锌矿结构;离子注入产生的相关缺陷在GaN:Mn薄膜中引起了新的声子模,分析认为Mn替代Ga位后所产生的相关局域振动紧邻GaN的E_2^(high)峰;测量显示材料具有室温铁磁特性,并且磁化强度和电学特性随着退火温度而变化。实验分析结合模拟计算表明,微结构随退火温度的变化引起相应的Ga空位和N空位浓度的变化,使得主导材料磁性能的交换相互作用发生转换,从而使材料磁化强度随着退火温度而变化。

GaN：Mn thin films were preparedvia implanting Mn ions into undoped GaN epilayers. The effect of annealing temperature on the microstructure, electronic and magnetic properties of the thin films was investigated. The results show that all the annealed samples have a single crystalline wurtzite structure without secondary phases. The new phonon modes in the GaN：Mn films are attributed to the vibrational mode of defects caused by the Mn ions implantation and Mn related local vibrational mode in the vicinity ofE2high. The GaN：Mn films exhibit room-temperature ferromagnetism, and their magnetic and electrical properties change with the annealing temperature. Analysis reveals that the alteration of material microstructure with post-annealing temperatures led to the variation of the magnetic exchange interaction, which made the ferromagnetism of this material system vary with post-annealing temperature.