【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.更多还原

【Abstract】 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.更多还原