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用分子束外延方法在GaAS(100)衬底上成功生长了高质量的Zn1-xMnxSe/Znse(x=0.16,x=0.14)超晶格结构.用X射线衍射和喇曼散射对其结构、应变分布以及光散射性能进行了研究.当超晶格的总厚度大于其临界厚度时,超晶格将完全弛豫至一个新的平衡晶格常数.此时,在(100)平面内,ZnSe阱层受到张应变,而Zn1-xMnxSe垒层受到压应变,从而,导致其喇曼光谱中,ZnSe阱和Zn1-xMnxSe垒的LO声子峰分别向低频方向和高频方向移动.当超晶格总厚度小于其临界厚度时,超晶格不再弛豫而是保持过渡层Znse的晶格常数,此时,ZnSe阶层不再受到应变,而Zn1-xMnxSe垒层受到压应变,在其喇曼光谱中,仅视察到ZnSe材料光学声子峰.本文从理论上分析计算了由这种应变引起的LO峰的频率移动,结果和实验所测值符合很好.
High quality Zn1-xMnxSe / Znse (x = 0.16, x = 0.14) superlattice structures were successfully grown on GaAS (100) substrates by molecular beam epitaxy. The structure, strain distribution and light scattering properties were investigated by X-ray diffraction and Raman scattering. When the total thickness of the superlattice is greater than its critical thickness, the superlattice will completely relax to a new equilibrium lattice constant. At this time, in the (100) plane, the ZnSe well layer undergoes tensile strain and the Zn1-xMnxSe barrier layer undergoes compressive strain, resulting in that in its Raman spectrum, the LO phonon peaks of the ZnSe well and the Zn1-xMnxSe barrier are respectively Low-frequency direction and high-frequency direction of movement. When the total thickness of the superlattice is less than its critical thickness, the superlattice no longer relax but maintain the lattice constant of the transition layer Znse. At this time, the ZnSe layer is no longer under strain and the Zn1-xMnxSe barrier is under compressive strain, In its Raman spectrum, only the optical phonon peak of ZnSe material was observed. In this paper, the frequency shift of the LO peak caused by this kind of strain is theoretically analyzed and calculated. The result is in good agreement with the experimental data.