【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(Ga1-xMnxN)were grown on sapphire [0001] by metal organic chemical vapor deposition(MOCVD).Mn concentration was determined by energy dispersive spectrometry(EDS).For Ga1-xMnxN 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 Ga1-xMnxN 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