【作者】 崔旭高； 张荣； 陶志阔； 李鑫； 修向前； 谢自力； 郑有炓；

【Author】 Cui Xugao,Zhang Rong,Tao Zhikuo,Li Xin,Xiu Xiangqian,Xie Zili,Zheng Youdou (Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Department of Physics,Nanjing University,Nanjing 210093,China)

【机构】 南京大学物理系江苏省光电信息功能材料重点实验室；

【摘要】 用MOCVD技术在[0001]取向的蓝宝石衬底上生长出Mn掺杂的GaN薄膜。测试结果表明,Mn掺杂浓度小于2.7%时没有第二相物质出现。Raman谱结果表明,由于Mn离子的介入,替换了Ga位的阳离子,从而使得A₁（LO）模的振动峰向低频方向移动。ESR结果表明,二价的Mn离子替换了三价的Ga离子,尽管如此,薄膜还是仅仅表现出顺磁性。通过Brillouin函数拟合以及ESR结果综合考虑可得,Mn在GaN晶格中的存在状态是孤立的二价顺磁性离子。更多还原

【Abstract】 Mn-doped GaN epitaxial films(Ga_1-xMn_xN) were grown on sapphire[0001]by metal organic chemical vapor deposition（MOCVD）.Mn concentration was determined by energy dispersive spectrometry（EDS）.For Ga_1-xMn_xN with x up to 0.027,no secondary phases except for GaN were detected by high resolution X-ray diffractometer（XRD）.Raman scattering spectra shows that the longitudinal optical phonon mode A₁（LO） of Ga_1-xMn_xN shifts towards lower frequency with increasing Mn concentration due to substitutional Mn incorporation.Room temperature electron spin resonance（ESR） measurements are performed and highly anisotropic six-fold hyperfine line indicates that the ionized Mn²⁺ substitutes for Ga³⁺ ions.However,superconductor quantum interference device（SQUID） magnetometry reveals that all homogenous Mn-doped GaN films show paramagnetic-like behaviors.From Brillouin function fit and ESR spectra,it is concluded that Mn ions are present as isolated paramagnetic centers.更多还原