低温分子束外延生长的GaMnAs反射光谱的低能振荡现象  

Low energy oscillatory phenomena in photoreflectance and photo-modulation reflectance spectra of GaMnAs films grown by low temperature molecular-beam epitaxy

作　　者：罗向东[1,2,3] 姬长建[2] 王玉琦[2] 王建农[1] 

机构地区：[1]香港科技大学物理系,香港 [2]中国科学院固体物理研究所,合肥230031 [3]南通大学专用集成电路设计重点实验室,南通226007

出　　处：《物理学报》2008年第8期5277-5283,共7页Acta Physica Sinica

基　　金：江苏省自然科学基金(批准号:BK2004403);南通市应用研究计划(批准号:K2007016);南通大学自然科学基金(批准号:07Z122)资助的课题~~

摘　　要：通过傅里叶变换红外光谱和光调制反射光谱技术测量了不同Mn含量的低温分子束外延生长在GaAs衬底上的GaMnAs样品的反射光谱.在低于Ga(Mn)As带边的红外反射光谱和光调制反射光谱上观测到低能振荡现象.通过分析振荡产生的原因并使用双层界面反射模型拟合了红外反射光谱的低能振荡过程,拟合结果与实验相符.研究表明,反射光谱的低能振荡是由于GaMnAs中空穴浓度的变化导致GaMnAs中的折射率发生变化,GaMnAs与衬底GaAs之间的折射率差导致了不同Mn含量的GaMnAs材料的反射谱的低能振荡现象.测量了不同GaMnAs材料在室温和低温下的光调制光谱,进一步说明GaMnAs材料中空穴浓度对反射光谱的低能振荡现象的影响.GaMnAs grown by low temperature molecular beam epitaxy have been investigated by Fourier transform infrared and photo-modulation reflectance（PR） measurements.Besides the band gap of Ga（Mn）As,Franz-Keldysh oscillations and spin-orbit coupling energy,low energy oscillations,lower than the GaAs band gap,were well observed in the PR spectra of GaMnAs.And these oscillations were also observed clearly in reflectance spectra of GaMnAs.By fitting the oscillations of the reflectance spectra,it was attributed to the variable refractive indexes induced by the high hole density in GaMnAs,which was caused by Mn doping in GaAs.At the same time,the PR spectra of high-resistance GaMnAs at low temperature were also studied.

关 键 词：GAMNAS 反射光谱 空穴浓度 折射率 

分 类 号：O472.3[理学—半导体物理]