高组分稀磁半导体Cd_(1-x)Mn_xTe/CdTe超晶格的荧光谱研究

Study on Photoluminescence Spectra of Cd_(1-x)Mn_xTe/CdTe Diluted Semiconductor Superlattices with High Mn Compositions

报道用分子束外延(MBE)技术生长的x=0.4,0.8的高组分稀磁半导体Cd1-xMnxTe/CdTe超晶格低温和室温荧光谱研究结果。基态激子跃迁能级荧光谱实验结果显示高组分超晶格中具有高量子效率和高质量光发射。对激子能级随温度的变化进行了详细研究,给出激子跃迁能量的温度系数。激子能级线型的展宽随温度变化关系可用激子-纵向光学声子耦合模型解释。与光调制反射谱实验结果进行了比较。

The electronic properties of Cd1-xMnxTe/CdTe semiconductor superlattices （SLs） with high Mn concentrations （x up to 0. 8） were studied by mearis of low and room temperature photoluminescence（PL）. The samples were grown by MBE on GaAs substrates with CdTe buffers. PL allowed the investigation of the optical emission from the fundamental 11H excitonic transition, revealing the high quantum efficiency and quality of the SLs. The temperature dependence of the excitonic PL energy position and excitonic line-shape broadening were studied. An exciton-longitudinal optical phonon couple model can be used to explain the experimental results very well. Photoreflectance （PR） spectra were also performed in order to compare with the authors＇ photoluminescence results. The combined use of PL and PR allowed a full understanding of the electronic states and optical emission characteristics of the authors＇ SLs. The authors＇ results indicate that high quality Cd1-xMnxTe/CdTe SLs with high Mn concentrations can be grown using MBE on GaAs substrates. The possibility to have magnetic semiconductor nanostructures opens the way to applications in the field of spintronics toward devices based on new concepts.